This is not an error message from perl, it is coming from a third-party product doing Remote Procedure Calls, so you will have to tie down the error to a section of code.

I suggest that you first try to reproduce the error, preferably in a single-threaded version of your program because debugging multi-threaded code is many times more difficult. Step through your code using the debugger, or insert print statements to STDERR to find where the message is coming from. Take one small step at a time, and don't expect to finish early tonight.