juts some advices from me
#1 replace images --> Trillix
#2 replace static text --> Trillix
#3 replace bitmap text --> Trillix (create a png file of translated bitmap text)
#4 replace dynamic text --> Quicker (edit the variable in actions script)why don't decompile .swf to .fla?
#1 decompiled .fla file may be broken when decompiled.
this possibly because of movie clip not decompiled correctly and actionscript incorrectly translated.
to fix this you have to check every script and every movie clip (you'll do a lot of debugging instead of translating
#2 font compatibility
the maker maybe use custom font that not available on your computer, the decompiler will replace it to similar one. the result my affect the size and position of the text which need to be refixed.
decompile may be good if you want to create a menu and copy a content from decompiled menu