Using Tracing provided by Logging and Instrrumentation Appln block in Web Application

[Samy]

I am trying to use tracing in the loggin and instrumentation
application block. I am using forms authentication. For some reason I
cannot write to the trace.log. I think I am running into permissions
issue. Under what account does the application run so that I can set it
for the trace.log??

Thanks a lot!!!