I have exactly same scenario....and same error.

I installed version 5.7.4 and workflow works, no errors. Ran the upgrade to 5.7.6 and go the same workflow error as before. Is it broke for everyone then?

It seems to work ok for me on a fresh install.

If I go to the dashboard and click workflow it just shows me the tabs and 'none' if I click on'waiting for me' it shows the same and if I click on 'Workflow List' it just informs me that I have 0 workflows.

This is a fresh installation with the sample content.

Are you able to post your environment information?

System & Settings > Environment > Environment Information

Sure I've been Playing around with it. I installed version 5.7.5.3 and workflow works with that version.

# concrete5 Version
Core Version - 5.7.5.6
Version Installed - 5.7.5.6
Database Version - 20151221000000

# concrete5 Packages
Supermint Theme (3.3.1.3).

# concrete5 Overrides
languages/sl_SI/LC_MESSAGES/messages.mo, languages/sl_SI/LC_MESSAGES, languages/sl_SI, languages/it_IT/LC_MESSAGES/messages.mo, languages/it_IT/LC_MESSAGES, languages/it_IT, languages/ru_RU/LC_MESSAGES/messages.mo, languages/ru_RU/LC_MESSAGES, languages/ru_RU, languages/el_GR/LC_MESSAGES/messages.mo, languages/el_GR/LC_MESSAGES, languages/el_GR, languages/pl_PL/LC_MESSAGES/messages.mo, languages/pl_PL/LC_MESSAGES, languages/pl_PL, languages/ja_JP/LC_MESSAGES/messages.mo, languages/ja_JP/LC_MESSAGES, languages/ja_JP, languages/fi_FI/LC_MESSAGES/messages.mo, languages/fi_FI/LC_MESSAGES, languages/fi_FI, languages/nl_NL/LC_MESSAGES/messages.mo, languages/nl_NL/LC_MESSAGES, languages/nl_NL, languages/pt_BR/LC_MESSAGES/messages.mo, languages/pt_BR/LC_MESSAGES, languages/pt_BR, languages/tr_TR/LC_MESSAGES/messages.mo, languages/tr_TR/LC_MESSAGES, languages/tr_TR, languages/da_DK/LC_MESSAGES/messages.mo, languages/da_DK/LC_MESSAGES, languages/da_DK, languages/fr_FR/LC_MESSAGES/messages.mo, languages/fr_FR/LC_MESSAGES, languages/fr_FR, languages/sv_SE/LC_MESSAGES/messages.mo, languages/sv_SE/LC_MESSAGES, languages/sv_SE, languages/de_DE/LC_MESSAGES/messages.mo, languages/de_DE/LC_MESSAGES, languages/de_DE, languages/sl_SI/LC_MESSAGES/messages.mo, languages/sl_SI/LC_MESSAGES, languages/sl_SI, languages/it_IT/LC_MESSAGES/messages.mo, languages/it_IT/LC_MESSAGES, languages/it_IT, languages/ru_RU/LC_MESSAGES/messages.mo, languages/ru_RU/LC_MESSAGES, languages/ru_RU, languages/el_GR/LC_MESSAGES/messages.mo, languages/el_GR/LC_MESSAGES, languages/el_GR, languages/pl_PL/LC_MESSAGES/messages.mo, languages/pl_PL/LC_MESSAGES, languages/pl_PL, languages/ja_JP/LC_MESSAGES/messages.mo, languages/ja_JP/LC_MESSAGES, languages/ja_JP, languages/fi_FI/LC_MESSAGES/messages.mo, languages/fi_FI/LC_MESSAGES, languages/fi_FI, languages/nl_NL/LC_MESSAGES/messages.mo, languages/nl_NL/LC_MESSAGES, languages/nl_NL, languages/pt_BR/LC_MESSAGES/messages.mo, languages/pt_BR/LC_MESSAGES, languages/pt_BR, languages/tr_TR/LC_MESSAGES/messages.mo, languages/tr_TR/LC_MESSAGES, languages/tr_TR, languages/da_DK/LC_MESSAGES/messages.mo, languages/da_DK/LC_MESSAGES, languages/da_DK, languages/fr_FR/LC_MESSAGES/messages.mo, languages/fr_FR/LC_MESSAGES, languages/fr_FR, languages/sv_SE/LC_MESSAGES/messages.mo, languages/sv_SE/LC_MESSAGES, languages/sv_SE, languages/de_DE/LC_MESSAGES/messages.mo, languages/de_DE/LC_MESSAGES, languages/de_DE

# concrete5 Cache Settings
Block Cache - On
Overrides Cache - On
Full Page Caching - Off
Full Page Cache Lifetime - Every 6 hours (default setting).

# Server Software
Apache

# Server API
cgi-fcgi

# PHP Version
5.3.29

# PHP Extensions
bcmath, bz2, calendar, cgi-fcgi, Core, ctype, curl, date, dom, ereg, exif, filter, ftp, gd, gettext, hash, homeloader, iconv, imagick, imap, ionCube Loader, json, libxml, mbstring, mcrypt, mysql, mysqli, openssl, pcre, PDO, pdo_mysql, pdo_pgsql, pdo_sqlite, pgsql, Phar, posix, Reflection, session, SimpleXML, soap, sockets, SPL, SQLite, sqlite3, standard, suhosin, tidy, timezonedb, tokenizer, uploadprogress, wddx, xml, xmlreader, xmlrpc, xmlwriter, xsl, Zend Guard Loader, zip, zlib.

# PHP Settings
max_execution_time - 60
log_errors_max_len - 1024
max_file_uploads - 20
max_input_nesting_level - 64
max_input_time - 120
max_input_vars - 1000
memory_limit - 168M
post_max_size - 32M
safe_mode - Off
safe_mode_exec_dir - /usr/local/php/bin
safe_mode_gid - Off
safe_mode_include_dir - <i>no value</i>
sql.safe_mode - Off
upload_max_filesize - 128M
mysql.max_links - Unlimited
mysql.max_persistent - Unlimited
mysqli.max_links - Unlimited
mysqli.max_persistent - Unlimited
pcre.backtrack_limit - 1000000
pcre.recursion_limit - 100000
pgsql.max_links - Unlimited
pgsql.max_persistent - Unlimited
session.cache_limiter - <i>no value</i>
session.gc_maxlifetime - 1440
soap.wsdl_cache_limit - 5
safe_mode_allowed_env_vars - PHP_
safe_mode_protected_env_vars - LD_LIBRARY_PATH
suhosin.cookie.max_array_depth - 50
suhosin.cookie.max_array_index_length - 64
suhosin.cookie.max_name_length - 64
suhosin.cookie.max_totalname_length - 256
suhosin.cookie.max_value_length - 10000
suhosin.cookie.max_vars - 100
suhosin.executor.include.max_traversal - 0
suhosin.executor.max_depth - 0
suhosin.get.max_array_depth - 50
suhosin.get.max_array_index_length - 64
suhosin.get.max_name_length - 64
suhosin.get.max_totalname_length - 256
suhosin.get.max_value_length - 512
suhosin.get.max_vars - 100
suhosin.log.phpscript.is_safe - Off
suhosin.memory_limit - 0
suhosin.post.max_array_depth - 50
suhosin.post.max_array_index_length - 64
suhosin.post.max_name_length - 64
suhosin.post.max_totalname_length - 256
suhosin.post.max_value_length - 1000000
suhosin.post.max_vars - 1000
suhosin.request.max_array_depth - 50
suhosin.request.max_array_index_length - 64
suhosin.request.max_totalname_length - 256
suhosin.request.max_value_length - 1000000
suhosin.request.max_varname_length - 64
suhosin.request.max_vars - 1000
suhosin.session.max_id_length - 128
suhosin.upload.max_uploads - 25

Postedhttps://www.concrete5.org/developers/bugs/5-7-5-6/workflow-error/...

Thanks for figuring this out! I'll update my php.

Hi,
Same error,
I can't change to php 5.4, does it mean i can't use Concrete 5.7?