The columns are:
[CommDrop] - Just and index, it starts and 1 and increments by 1 for each entry.
TerrainIdx - No idea but it seems to be 0 a lot
ItemKind - The item number
ItemOpt - The itemOpt (the same as you use in the cabalcash tool)
DropRate - The droprate
MinLv - Min char level needed to actually get the drop maybe?
MaxLv - The max level to get the drop?
Group - Not sure but it will be an index in anotehr file somewhere
MaxDropCnt - Max number of the item that can drop?
OptPoolIdx - Index from the optionpool file
DurationIdx - Duration index from that file, the same values as the cabalcash tool again.
The rate is from 1.0 to 0.000000000blah so just make the number higher. As with the general droprate do not just stick them all at a high number as this will just break things worse, increment the number slowly until you are happy with the rate.