"and with translation to differnt languages also comes problem of user support...
if user doesn't know english well enough to use FlashFXP and he'll come here or email looking for support chances are it'll be very hard for that user to explain in english what his problem is..."
I am gonna tell you that my experience is that if the user knows the translator's name and e-mail address (e.g. from the language file or from the website, he/she contacts the translator to help in solving the problem.
By the end of the localization the translator will know the program from alpha to omega, because he has to test it, and when a problem occurs he can provide support for the user. This way the developers may have less work in the support
By chance, the translation of the help file also would be advisable.
Anyway the users are very grateful for the localization, so I think they would appreciate the languages sooner.
From the business aspect a well prepared affiliate program would facilitate the sales for the non-English-speaking users.