See the post on this site:
Jobs - embed TSQL or Call Stored Procedure??
Posted 3/15/2004 7:12:00 AM
Looks like someone with the same problem but I don't think they attained a complete solution.
Rather than persevering with a workaroubnd for the problem, I think you will be better off filtering out the error before your procedure starts by cleaning the source data accordingly in a staging area.