loss of email filtering rules for Outlook 2002

I'm running Outlook 2002 on Windows XP Home Edition. When I
first installed, everything worked fine. A day later, I got
an error message stating

"An extension failed to initialize. Can't open file:
extend.dat. The file may not exist, you may not have
permission to open it, or it may be open in another
program. Right-click the folder that contains the file, and
then click Properties to check your permissions for the
folder. You don't have appropriate permissions to perform
this operation."

The file exists, I am an administrator on this computer,
and the folder permissions are set to read and write.

The error message also coincided with the loss of all my
email filtering rules. In fact, the rules wizard option
disappeared from my Tools menu. I tried removing nad
reinstalling Office 2002, but the problems persists.

Help! I get too many emails a day to not have my filtering
rules.

Thanks,

Travis