Get this:
http://w1.369.telia.com/~u36902706/MannIdentD.rar
Its a small Ident server tha will handle all Ident requests on your computer.
Unpack to a folder. Add the exe to autostart. Run the program. Right click on it to enter your values. Turn of ident in both mirc and flashfxp.
Works flawless for me and have done so for +1 year now.
There are ofcourse other Ident servers like this but this one is small and does the job.
Hope it helps.