The file you have chosen is not an Plus company file.
Troubleshooting Alert Messages Overview > Alert messages (in alphabetical order) > The file you have chosen...If you haven't already done so, we suggest you read the Troubleshooting Alert Messages Overview.
Situation: The file you attempted to open isn't a valid MYOB Plus company file, and can't be used by the version of MYOB Plus on your workstation.
Solution: You can't open this file using MYOB Plus. Click OK to close this message, then attempt to open a valid MYOB Plus company file.
The file you have chosen is not an MYOB Plus company file.