You should be able to use asterisks, but it seems like that might be broken in the latest version. We'll look into that further.
In the meantime, you can enable the "Treat all Exclude Path filters as wildcards" option on the Settings > Search tab, then just put the text you want to exclude in without asterisks.
For example, if you're searching the C:\ drive, but don't want to search any folders with "Program" in the name, just put "Program" in the Exclude Path box after enabling the setting above
Last month we released FileSeek 5.1 (http://www.fileseek.ca/Download) and this issue should be all fixed up. Please let us know if you run into any trouble after updating.
