PE2650 Broadcom NIC, Windows 2003, and UNC Share Issue

Here's my setup:

PE2650
Windows Server 2003
BroadCom Gig NIC

I have a web site in IIS with its Home Directory pointing to a UNC share. The UNC share resides on a NetApp R100 filer. After a few hours, the PE2650 can no longer read files located in the root of the share (ex. \\somefiler\webfiles\). However, it can read files in subfolders (ex. \\somefiler\webfiles\app1\). Restarting IIS seems to be the only fix. Also, the amount of time it takes for the problem to crop up varies - the server can go hours or days without seeing the problem. But eventually it happens.

I've narrowed the problem down to the Broadcom NIC and Windows 2003. These are the results I've experienced with different configurations:

Windows 2000/Broadcom NIC - No problem
Windows 2003/non-Broadcom NIC - No problem
Windows 2003/Broadcom NIC - Problem
Windows 2003/Broadcom NIC/Pointing to different UNC share - Problem

Regards,
Erick