Tracking 500 Errors

I have been trying to diagnose some sporadic “Rails application failed
start properly” errors, and this is what I have been able to determine.
am running on a shared server on site5, apache w/ FastCGI. When my
application is running, it is only using 1 dispatch.fcgi process until I
upload a picture. At that point, between 3-4 more dispatch.fcgi
are spawned and the 500 errors are being caused as these extra processes
slowly die off. So, now my couple of questions. What causes these
additional processes to be spawned? What causes the process to die?
anyone been able to solve this problem? Thanks for any help!