The easiest thing to do is tell your vendor to stop sending you invalid files.
There are many ways of handling errors in SSIS. Not sure if you can come up with one that would detect if an error is caused by this condition and not another condition that you do not want to ignore.
For best practices on asking questions, please read the following article: Forum Etiquette: How to post data/code on a forum to get the best help[/url]