I just did a first install of Concrete5 - concrete5.7.5.10. All the test passed and when hit install I got the error - {"error":false}{"error":{"message":"Module 'calendar' already loaded"},"errors":["Module 'calendar' already loaded"]}

I was able to complete the install and it runs but at the bottom of some pages i get the error shown above.

Here is the enviroment:

# concrete5 Version
Core Version - 5.7.5.10
Version Installed - 5.7.5.10
Database Version - 20160615000000

# concrete5 Packages
None

# concrete5 Overrides
languages/pt_BR/LC_MESSAGES/messages.mo, languages/pt_BR/LC_MESSAGES, languages/pt_BR, languages/fr_FR/LC_MESSAGES/messages.mo, languages/fr_FR/LC_MESSAGES, languages/fr_FR, languages/da_DK/LC_MESSAGES/messages.mo, languages/da_DK/LC_MESSAGES, languages/da_DK, languages/es_PY/LC_MESSAGES/messages.mo, languages/es_PY/LC_MESSAGES, languages/es_PY, languages/it_IT/LC_MESSAGES/messages.mo, languages/it_IT/LC_MESSAGES, languages/it_IT, languages/fi_FI/LC_MESSAGES/messages.mo, languages/fi_FI/LC_MESSAGES, languages/fi_FI, languages/tr_TR/LC_MESSAGES/messages.mo, languages/tr_TR/LC_MESSAGES, languages/tr_TR, languages/de_DE/LC_MESSAGES/messages.mo, languages/de_DE/LC_MESSAGES, languages/de_DE, languages/sv_SE/LC_MESSAGES/messages.mo, languages/sv_SE/LC_MESSAGES, languages/sv_SE, languages/ja_JP/LC_MESSAGES/messages.mo, languages/ja_JP/LC_MESSAGES, languages/ja_JP, languages/cs_CZ/LC_MESSAGES/messages.mo, languages/cs_CZ/LC_MESSAGES, languages/cs_CZ, languages/ru_RU/LC_MESSAGES/messages.mo, languages/ru_RU/LC_MESSAGES, languages/ru_RU, languages/en_GB/LC_MESSAGES/messages.mo, languages/en_GB/LC_MESSAGES, languages/en_GB, languages/es_ES/LC_MESSAGES/messages.mo, languages/es_ES/LC_MESSAGES, languages/es_ES, languages/nb_NO/LC_MESSAGES/messages.mo, languages/nb_NO/LC_MESSAGES, languages/nb_NO, languages/nl_NL/LC_MESSAGES/messages.mo, languages/nl_NL/LC_MESSAGES, languages/nl_NL, languages/es_PE/LC_MESSAGES/messages.mo, languages/es_PE/LC_MESSAGES, languages/es_PE, languages/pl_PL/LC_MESSAGES/messages.mo, languages/pl_PL/LC_MESSAGES, languages/pl_PL, languages/el_GR/LC_MESSAGES/messages.mo, languages/el_GR/LC_MESSAGES, languages/el_GR, languages/pt_BR/LC_MESSAGES/messages.mo, languages/pt_BR/LC_MESSAGES, languages/pt_BR, languages/fr_FR/LC_MESSAGES/messages.mo, languages/fr_FR/LC_MESSAGES, languages/fr_FR, languages/da_DK/LC_MESSAGES/messages.mo, languages/da_DK/LC_MESSAGES, languages/da_DK, languages/es_PY/LC_MESSAGES/messages.mo, languages/es_PY/LC_MESSAGES, languages/es_PY, languages/it_IT/LC_MESSAGES/messages.mo, languages/it_IT/LC_MESSAGES, languages/it_IT, languages/fi_FI/LC_MESSAGES/messages.mo, languages/fi_FI/LC_MESSAGES, languages/fi_FI, languages/tr_TR/LC_MESSAGES/messages.mo, languages/tr_TR/LC_MESSAGES, languages/tr_TR, languages/de_DE/LC_MESSAGES/messages.mo, languages/de_DE/LC_MESSAGES, languages/de_DE, languages/sv_SE/LC_MESSAGES/messages.mo, languages/sv_SE/LC_MESSAGES, languages/sv_SE, languages/ja_JP/LC_MESSAGES/messages.mo, languages/ja_JP/LC_MESSAGES, languages/ja_JP, languages/cs_CZ/LC_MESSAGES/messages.mo, languages/cs_CZ/LC_MESSAGES, languages/cs_CZ, languages/ru_RU/LC_MESSAGES/messages.mo, languages/ru_RU/LC_MESSAGES, languages/ru_RU, languages/en_GB/LC_MESSAGES/messages.mo, languages/en_GB/LC_MESSAGES, languages/en_GB, languages/es_ES/LC_MESSAGES/messages.mo, languages/es_ES/LC_MESSAGES, languages/es_ES, languages/nb_NO/LC_MESSAGES/messages.mo, languages/nb_NO/LC_MESSAGES, languages/nb_NO, languages/nl_NL/LC_MESSAGES/messages.mo, languages/nl_NL/LC_MESSAGES, languages/nl_NL, languages/es_PE/LC_MESSAGES/messages.mo, languages/es_PE/LC_MESSAGES, languages/es_PE, languages/pl_PL/LC_MESSAGES/messages.mo, languages/pl_PL/LC_MESSAGES, languages/pl_PL, languages/el_GR/LC_MESSAGES/messages.mo, languages/el_GR/LC_MESSAGES, languages/el_GR

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

# Server Software
Apache

# Server API
apache2handler

# PHP Version
5.6.28

# PHP Extensions
apache2handler, bcmath, calendar, Core, ctype, curl, date, dom, ereg, fileinfo, filter, ftp, gd, gmp, hash, imap, ionCube Loader, json, libxml, mbstring, mcrypt, mhash, mysql, mysqli, mysqlnd, openssl, pcre, PDO, pdo_mysql, pdo_sqlite, Phar, posix, Reflection, session, SimpleXML, sockets, SPL, sqlite3, standard, tokenizer, wddx, xml, xmlreader, xmlwriter, xsl, zip, zlib

# PHP Settings
max_execution_time - 30
log_errors_max_len - 1024
max_file_uploads - 20
max_input_nesting_level - 64
max_input_time - 60
max_input_vars - 1000
memory_limit - 256M
post_max_size - 8M
sql.safe_mode - Off
upload_max_filesize - 2M
mysql.max_links - Unlimited
mysql.max_persistent - Unlimited
mysqli.max_links - Unlimited
mysqli.max_persistent - Unlimited
pcre.backtrack_limit - 1000000
pcre.recursion_limit - 100000
session.cache_limiter - <i>no value</i>
session.gc_maxlifetime - 1440