I just placed a TextAloud update at http://www.nextup.com/files/ta3.exe
that should fix the problem you're having with saving the dictionary. Please try installing this update and make sure you can save the dictionary without needing to rename it.
The crash message you're seeing is looking like it is coming from the Acapela voice engine, so not sure why that would be happening. If you continue seeing this error after installing the update, please send me a problem report from TextAloud. From the help menu, click Help -> Support -> Report A Problem, and just reference this issue in the problem report text.