Weird Weird behavior (1 Viewer)

This is a strange one:

Assume that the following directory is empty:
R:\claims\projects\xxxxx xxxxx\data\V F P 12

If I try to execute the following command in VBA, it works fine:
DoCmd.TransferSpreadsheet acExport, , "tblReturnedMail", "R:\claims\projects\xxxxx xxxxx\data\V F P 1234567890 1234567890\ReturnedMailVFP.xls", True

However, if the pathname is 1 character longer:
R:\claims\projects\xxxxx xxxxx\data\V F P 123

I get the following error message:
"Cannot update. Database or object is read-only."

If the file already exists in the directory, I can apparently chabge the length of the pathname to whatever I want. For example, the following works (if the xls file is already there):
DoCmd.TransferSpreadsheet acExport, , "tblReturnedMail", "R:\claims\projects\xxxxx xxxxx\data\V F P 1234567890 1234567890\ReturnedMailVFP.xls", True

Any ideas?
Thanks in advance.