Sometimes InfoPath Forms Server (IPFS) gives you a non-descriptive error when you try to admin-publish a form using the "Manage Form Templates" UI in SharePoint Central Administration. These steps could provide a more informative error message.

Deploy the solution via stsadm. First time installations should use uploadformtemplate; otherwise use upgradeformtemplate:

stsadm -o uploadformtemplate -filename ...
stsadm -o upgradeformtemplate -filename ... -upgradetype overwrite

This has to be done from the SharePoint machine. Typically stsadm lives in this folder: C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN

For example, if the dropped solution is located on a machine from which the admin is term-served from, this can be used (modify the path as needed):

stsadm -o upgradeformtemplate -filename "\\tsclient\C\SScore.xsn" -upgradetype overwrite