Unfortunately that's the same for older versions of Excel. I just tried with Excel 2003, 2007 and 2010 RTM to prove a point and get an identical erorr message in all cases.
You can't have a <>?:|* in the filename / path as those are either illegal in Windows or would screw up Excel files being linked to one another (since for example square brackets are used to identify the workbook in an external link)
edit:To be a little clearer, you can have a square bracket in a file name or folder name, but you can't have a [ as the first character of a folder name since this would be ambiguous in external links.
"[My Folder]" is not allowed, "![My folder]" is fine (for example) so you might be able to rename your folders in such as way as to retain their origial implied "meaning" (and sort order) and keep Excel working.