After an unusual long waiting time, Yahoo patches for all Trillian versions have been released.
Patch F is available for Trillian Basic 0.74 users. There's also a 0.74f package for new installations.
Patch E is available for all users of Trillian Pro 1.0. The new patch for Trillian 2.0 resolves all issues and should also be installed if a beta patch is already in use.