Please get the latest version, because that is good practice, however it is not likely to solve this.
It sounds like you have multi threads running on the DNN site.
There is a post here that talks about multi thread
http://www.packtpub.com/article/under...
Please try setting the:
maxThreads: This sets the maximum number of thread-pool threads to be used by the scheduler (
1-10). Setting it to
-1 tells the scheduler to determine this on its own.
Change it to 1 and report to us the result.