As requested, adding the glitch I found...after another thank-you for you folks providing such an incredibly-useful tool!
I was trying to add a powerset from Beta. I went to Options, Advanced -> Database Editor, Main DB Editor, clicked MM Summon, hit Add under the set, entered the set's info, display name Beast Master, set name Beastmaster, set the AT and all, and clicked OK. It went 'Bonk! Invalid Name'. However, it made the 'Beast Master' entry! The set name was blank, though.
Attempts to add a power to it would universally bomb with an invalid name. I have deleted it safely, thankfully. Thanks for offering to look into it! I'll happily help test stuff, or forward files or whatever if it might help. Just let me know.
-liz