Crystal Reports and w3wp

[Carmen]

We have an application running in a Windows 2003 Server with IIS 6.0. The
application exports Crystal Reports reports to pdf files. It works fine for
a while, 1 or 2 days, after that, the application is unable to generate and
export reports and, we need to reset w3wp process. After reseting the w3wp
process the application begins working fine for another 1 or 2 days.

What can we do?

Thanks in advance,
Carmen.