Really stumped on this issue I have been having. 

I have an external system that creates a file that gets imported into Sage through a VI job. It has happened a few times where a user will go to create the file and then when trying to import it, the record fails. The vi job error fails states the the Customer Number contains an invalid character. In the file though there are no invalid characters - or at least it doesn't appear to be - the customer number is in this format 0000.00

When I have another user go re-create and process the same file in the external system, they are able to import it correctly into sage without any problem. And the customer number is the same. 

I had the user that experienced the problem log into another computer and try and process it and it still fails.

Most of the time the vi job processed the external file with no problem at all. 

I am not entirely sure what system the issue is happening at but figure I would start here to see if anybody else every has an issue where they sometimes import a file and it says there are invalid characters. I also don't know if this helps or not but the users that have reported the issue are running windows 7.