FileMaker Inc. does not provide any support for any form of FileMaker 5.5. It's just too old. (Current release of Filemaker is FileMaker 11.)
Do you have a copy of FileMaker 5.5 for windows?
If so, you should be able to just copy the files over and open them up. The files and scripts should function just fine, but you may find that you need to modify layouts a bit as Windows systems need a bit more space to display the same text so you may find some text is wrapped or clipped until you make some small adjustments. Also, if your database uses fonts that don't have an equivalent installed on the windows system, Filemaker will substitute a different font and this will require you to make some layout adjustments.