Just to close this post I thought I would post the solution I found in case anyone else has the same issue. Turns out somehow the problem I was having was because I was using the vodafone browser. As I have no other on the BB then the mobile download was scuppered. I found however on the beiks page an option to get a PC download by sending my e-mail address and was then sent a link for an .exe download.
I then successfully downloaded onto PC then onto BB via desktop manager.
Lexspell looks great and after a couple of days if things are still okay I will gladly pay the $10 registration.