I have recently had to manually delete an early version of Tweetcrete that was causing a problem. It is not showing up in the block types anymore which is good. What is not good is that it is showing up in the Install page, twice in fact, the early version and the current version (which I have not installed at all). When I click the edit button nothing happens so it appears I can't get rid of them. I have tried deleting the cache to no avail.

Any ideas on how to get rid of them would be much appreciated.