pc to tv wireless sender problem

hello,i have a pc to tv wireless sender (DV-200)and i`m having problems. i have contacted the people who i purchased it from, www.simplyautomate.co.uk and also the people who made it www.pcsender.net ,both very helpfull but my problem is a new one to both of them, that they have never heard of this, hence my plea to you lovely people.
when connected (all variations have been tried from 2 laptop`s,home pc/main tv and portable) the monitor display shows on the tv,media player shows but when a dvd/movie file/avi file/mpeg etc is played there its just a black screen( media player is still showing on tv) . the only images that sometimes work is little 1 min vid clips from i-am-bored.com,i`m totally stumped...any takers?
thanks in advance

 

opps sorry,here is my spec.....win xp sp2, 3.00GHz pen 4 acer travel mate 2700 ,192 Megabytes Installed Memory,
16 kilobyte primary memory cache
1024 kilobyte secondary memory cache, MOBILITY RADEON 9000/9100 IGP [Display adapter]
Default Monitor (2x)
Hitachi 15.4 [Monitor] (15.4"vis, October 2004)