Admin-given memberships expire in less than a day

Hi,

I've got a problem with accounts I've been giving monthly and yearly memberships to with my admin privileges. They seem to expire in a day or so.

When I check the "profile" in the members area of protected content, whether monthly or yearly, there is a join date with no expiration.

Paid users show expiration dates, it's just for memberships I've given out as admin.

I'm not terribly techincal, there are some memberships I granted as an admin that show an expiration date, but these happened before our site was moved to a new server. I have a feeling the w3 total cache plugin may be interfering.

Any ideas appreciated!

Thanks,
Tim