I have the Nitro PDF Professional and experience loads of problems. The first issue i had to return to Office Max and they gave me the 6.0 version due to so many issues with the first they were actually pulled off of the shelf.
The program freezes up,
it reverts to foreign language on it's own,
stops responding when you want it to open,
and in order to kick start it again you must restart your computer.
I have installed it on 2 computer's and it does the very same thing on both. The support is non existent and try and look for a number...ya right! Good luck. Don't waste your money ,
and if anyone says it's a good program they probably work for them...don't listen.