This may seem silly but do you have active scripting allowed in your browser?
(oh and Esks....)The ads work when I visit your site...
in IE.

Also RAG:
Make sure you select the HTML option if you are placing it in a block....

Sorry guys. I've tried just about everything. I can view the ads in other XOOPS site listed above, but not on mine. I've picked the HTML option for block...and so on. Any ideas anyone? ESK?

I tried your site,http://www.bpoforum.org, and it all worked. I saw the Google Adsense on the left and at the bottom. I'm using IE ver5.5. I guess you got it working. The only problem I saw was the center blocks seem to overlap on the left and right blocks. This same thing happens to me when visiting the XOOPS site. Also when I first started using XOOPS the theme I used had the same problem. I then made the table width 99% and it fit perfectly within the browser. No bar at the bottom.