If the change settings in CPA don't work, first try to hook another keyboard which you know for sure it has no midi timing problems.

Also CPA 6.0 is an old version which could have some problems with todays O/S (win98)

You could post the problem in the Roland JV Section on this BBS, as I can remember someone having simular problems! which had to do with a setting on the JV2080.
I don't own a JV2080 so I cannot recall this.