Drive Shares Disconnecting on Domain

Hi,
Had a ME machine used to backup our SBS server drives on a nightly basis.
Worked for 2 years.

A virus required me to wipe out ME and reinstall.

Everything was reset up, but for some reason, the drive mappings to the
server will disconnect after a period of time. No error messages on the ME
machine or the SBS server.

If I reboot all the shares come back. If I logoff, the shares will not come
back.

I haven't seen or heard of this before. The time frame seems to be between
8-6 hours before it disconnects.

thanks for any insight one might bring to this.