It sounds like Access has an issue with the data format of the file you're trying to import.
Try this: make a copy of that file and manually change the extension to .txt and try to import it using the wizard. If the data comes up gibberish you'll understand why Access has an issue with it. If not, go through the motions and create an import specification and save it. Then try importing the original file in VBA using the import specification you just created. By the way, what are your exact entries for "tablename" and filepathname? There might be an issue with them also.