Message no. GMAVC016 While releasing Budget Supplement In Grants Managemnt

HI,

My client is trying to add supplement to a grant by using T-Code "GM_BDGT_RELEASE - Release Budget". While releasing the supplement the system gives the following "WARNING MESSAGE"

Overall budget of 1,000.00 PKR(GM PB Availability Control) almost exhausted for document item 000001

Message no. GMAVC016

Diagnosis

The current budget consumption is 1,000.00 PKR (GM PB Availability Control) less than the overall budget for the document item 000001. Availability control on outgoing amounts raised this message for the following combination of availability control ledger, fiscal year, and control object:

Please also not that Grant Validity is from "01.05.2013" to "31.12.2013" so the grant is still valid and the posting date for releasing the supplement is 12.12.2013.

Why is the system giving me this warning? there is still a remaining budget of 700 PKR in the target sponsor class.

Help please.