Constant Rejections by BCBS

Does anyone else bill BCBS for substance abuse? We are constantly getting rejections by BCBS, and the status is always vague:

Error Message:         Category: Acknowledgement/Rejected for Missing Information  The C
laim/Encounter is missing information specified in the Status details and has been rejec
ted Status: Information submitted inconsistent with billing guidelines. Note: At least o
ne other status code is required to identify the inconsistent information.

This happens to probably 75% of the claims I bill out, and I can't seem to pinpoint why...