OH, if its imbuing then it is probably your imbuing menu being left up.
The Kill gump probably doesn't properly Close it, so the game still thinks that it is open.
it won't let you use another skill while the Gump is open.
Your Best bet with Imbuing is to wait for the Gump to Reopen after every Time you use it, and Close it. if that makes sense.
Manwinc, you're right on the mark on all counts. I was using event macro 31 to kill all gumps, but when you mentioned that the kill gump doesn't properly close it - I was able to reproduce the problem immediately and without fail every time. Event macro 31 works great on every gump I've come across - except Imbuing. In fact, I was using em31 to close gumps after each of 5 Craftsman skills, but only the Imbuing gump would cause the "you must wait to use another skill" mandatory reboot. But come to think of it, all the normal craftsman gumps were created at the same time - no doubt by the same team. And the Imbuing gump came years later... Guess they just don't make coders like they used to...

Anyway, problem solved...
It would help others if this info was contained in a
footnote in the
WikiDocs...