Stock ledger is messed up

We are using v6 of erpnext. There is some problem related to valuation rate and thus my whole stock ledger is messed up. Can anyone suggest me some method to correct those stock ledger entries.

You need to explain what is the problem in detail/

Usually its Garbage-in-garbage-out - if you messed up valuation rates at input, they will be messed up!

A quick fix is to make a Stock Reconciliation at a particular date with the correct rates and move on.