Skype WebMessenger on Blackberry incomplete calls

Hi

I have installed webmessenger v. 2.4.1012 on my BB 7290 (OS v. 4.10.256)
along with the helper application on my winxp desktop. I have imported my
buddy list ok and can see their online status. However when I try to make a
call from my BB the initial connection is made and is received on my buddy's
skype however the call is dropped within 1 or 2 seconds, there is also no
ringing tone on my BB whilst the call is being initiated. I can also call to
my BB from another Skype account and the call is received but then dropped
almost immediately

Does anybody have any ideas as to what I am doing wrong, has anybody got
this combo to work?

Thanks a lot
Simon