The title of this thread sounds more interesting than its topic.
Several people have posted today telling me they are having trouble with the Hydrans after installing Squadron Commander v1.3. I'm not sure what the issue is, but I have a manual fix posted in the Squadron Commander INstallation files thread at the top of the page.
I'll investigate and repair when I get home tonight, but the posted fix will get you playing again.
-S'Cipio