an error occoured when the workflow was being created. try to save the workflow again

an error occoured when the workflow was being created. try to save the workflow again

As per microsoft this is regression issue of update rollup2
And the fix is adding a entry to MS CRM web.config file
for details

http://social.microsoft.com/Forums/en-US/crmdevelopment/thread/e0a8b1f3-5bbf-4040-ab5c-2a67df362b5b

or

https://community.dynamics.com/forums/p/11935/16202.aspx