here i give the message no and details
Message no. AA660
The document cannot be posted, as it is contrary to the net book value rule which is checked in area 15.
This error usually occurs when you enter proportional values. The proportional values exceed the amount posted, for example, post capitalization of 100 but proportional depreciation to the amount 110. Check your entries and correct them if necessary.
pl clarify the term of proportional values assets with example. i am not able to understand this error.