Diagnosis
The variant program expected a certain number of document line itemtypes. However, the number of document line item types actually definedfor this variant differs from the expected number.

Procedure
Check how many document line item types have been defined for therelevant item using transaction EA88.
Also check in rate whether the number of document line item typesdefined for this variant matches the expected number.
If everything matches the expected number, then an error has probablyoccurred in the billing program.
Otherwise the setting in the system tables for variants is eitherincorrect, or the setting changed without the necessary changes beingmade in the rate or variant.
In any case, report this error to SAP.