Getting an error when importing .AI file into Photoshop

I recieved an email attach AI file that I tried saving to my HD and then opening the .AI in Photo shop 7. PS 7 recognized the file but when I went to open it a Msg came up that said---Could not open file.....because the parser module cannot parse the file--- ???? Any suggestions...Dave

Does the file open with Illustrator? It's possible the file got corrupt during email transfer, the fix is to compress the file before emailing.