softech template help

Hello all,
I bought the softech template (Paypal transaction ID 00G13623H6846701F)and have installed it at siteground.com using joomla 1.5 installer. I am having problems with it. I cant seem to change the overall color scheme (editing the template from template manager gives me an error that parameters.ini file is not writable!? , and the drop down list where I can supposedly choose colors shows blue, orange, and 5 greens). Also, for some reason, when I load the home page, the colorful banner doesnt show up (only some black boxes where the banner should be are visible). For an example, see http://75.125.62.4/~orcristb/. I am frustrated because Im not a technical wizard, and everything I read about joomla and template installation suggested to me that it was supposed to be EASY!

Thanks for any suggestions.