Visualiser MIDI to RS232 lead help needed

[chaos john]

hiya everyone just a little help needed here,
im running visualiser on a pearl 2000 upgraded to 2004 software through a Visualiser MIDI to RS232 lead, the problem ive got is wheel no2s DMX % rises on its own, on whichever attribute youve got it on , which is well annoying when your trying to programme a show,

has anyone else experianced this problem and knows of a cure
or have i got a prob with Desk/lead/pc any ideas anyone

john