Create Accounting Completed with Warning

I am trying to run Create Accounting request from AR module. But it is completing with warning. Below is log file of warning.

The following REVERSAL events could not be processed. The event/process status is U/U:

Note: this warning may be ignored for any events whose ledger is a cash-basis ledger

Event XXXXXXX of ledger XXXX

while checking the interface line from AR, 2 lines are stuck in AR interface line. Please suggest how to resolve these error.

AR Interface Line Error:

Line 1: You must supply conversion rate when you supply conversion type of type User.

Line 2:      The total amount of your credit memo cannot exceed the balance of the debit item it is crediting