SE-S2000 CV10 programming issue

HI
I have just connected my SE-S2000 upto a metrologic scanner, and if I manually program the till PLU's via the till the scanner works fine. So I decided to get the CV10 s/w and cable to speed the process up! I have the till and PC communicating, and send receiving files. I have tried editing the PLU file on the PC including scanning barcodes into it (only done 5 PLUs as a test) When I send the file back to the till and try scanning a product it comes up with unknown PLU. As I wasnt sure if the files were sending and receiving correctly, I uninstalled CV10, set it up from scratch and re downloaded the DATA from the till. My PLU edits were there (so they are being stored on the till!) Strangley the manually added itrems(done via the Till and not the PC/CV10) are not showing in any of the files, but still scan in OK on the till! What am I doing wrong??? Any help would really be appreciated, before I chuck the whole lot out the front door LOL