cant use "Click Me" hands/logos

Hi,

I'm trying out Second Life for the first time.

However, I am unable to click the "Click Me" hands/logos.

Other problems I am having are that my avatar is just a black silhouette, and sometimes the landscape goes a funky psychedelic pattern or green grid.

Suggestions?

TIA

After more investigation...

I cannot grab things, as per the ball exercise near the exit pergola on Orientation Island. Additionally, I cannot exit Orientation Island or go to Help Island.

I am using the latest Linux Client Alpha on Ubuntu Edgy. The machine is a Compaq Presario laptop (ati radeon xpress 200m).

Please help.