problem canceling a FA Entry


We are using Nav2009, SP1

A few days ago I posted using FA journal(acuisition cost and depreciation) from data migration with FA posting date 29/02/12.

and also posted a monthly depreciation using FA G/L journal for just one asset Fa no.10 on 31/03/12.

Now, since the date of the Fa entries was wrong, i had to cancel them, but this monthly depreci. i did for  that asset is preventing it.

The FA situation is as below:

The first two lines are the intial entries with FA journal, the third one is the depreciation cancelled with FA journal.

The fourth is march depreciation using FA g/L journal, last one is the reversed entry of the fourth line

FA Posting Date Depreciation Book Code FA No. FA Posting Type Amount
29/02/2012 DEF_DEPR FA00010 Acquisition Cost 1,718,967.75
29/02/2012 DEF_DEPR FA00010 Depreciation -334,243.73
29/02/2012 DEF_DEPR FA00010 Depreciation 334,243.73
31/03/2012 DEF_DEPR FA00010 Depreciation -23,875.00
31/03/2012 DEF_DEPR FA00010 Depreciation 23,875.00

I cannot cancel the first line because there is a NAV message:

"Book Value should not be negative or less than Salvage values for the asset no.10....." and while trying various ways there is also another message"

First entry mus be an Acquisition Cost for FA no.qq0..."

Pleasee, can anyone help on this problem?

thanks in advance