My first swag is that this is just a file naming issue.
Valid filename characters for FAT32 AFAIK are A-Z,0-9 and ~!@#$%^&()_-{},.=[]`' and a space. So "?;:/\+ are invalid but if other characters are having problems then I would not know on which side the problem might lie. It might be that the vfat module only allows 8.3 FAT characters which does not include +,=[].
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