Offline files not available as an option

I thought make available offline was an option under tools in my computer or
explorer. I dont have it on my xp pro sp2. When I go to the offline
files tab- the make available offline is greyed out. This is in a windows
2003 domain. I checked my local gp thru gpedit.msc and both user and
computer config for offline files are set to not configured.

Any idea where to look further??

Thanks

Carlos