Exchange Errors every few seconds

We have several locatons, each with MS Exchange running on an NT4 Server. On one location, we keep receiving application errors every few seconds. I have done everything I can possibly do, but still have not gotten rid of the problem. The errors are logged as information and some of the error numbers are #2163, #2125, #3200, and #2169. What can I do to alleviate this problem?