http://www.swf2flv.net
if you have flash swf source files... fla files you can export them to avi format as Flash CS3 / File / export / export movie / drop-list / choose flv to complete the conversion.
but if you have only swf files and not the source, you should use a professional conversion tool. you can try iwisoft swf to flv converter which works well for me, maybe it can solve your problem as well, good luck !
Code:swf2flv.net