"The timesheet creation failed, because of problems with the project server or with data validations, such as resources not being valid work resources or users. Check your environment, and then try again".
I knew this issue in the past. I was always able to get it solved by using
surrogate timesheets. Sometimes it took serveral runs of deletion and
recreation.
Now I can only tell to install at least CU February (of course there is the
newer one from April which includes February updates!!!), which addresses
this issue. Have a look at the description http://support.microsoft.com/kb/978397.
