felted-bag

Hello, I tried to install the trial version of LingvoSoft Talking
Translator 2007 English <-> German for Pocket PC and I am getting the
following message on my Dell Axim x51v - running Windows Mobile version 5:
"installation was unsuccessful. The program or setting cannot be installed
because it is not digitally signed with a trusted certificate."

When I email Lingvosoft about the problem -- this is the answer I got:
"We cannot help in that case. Our programs currently do not have Microsoft Certificate. Probably you need somebody who can unlock your system."

What do I need to do on my end? Thanks for your help.