installed - logged in, but index.php is blank...

Hi. I thought from reading through the spec that PowerCMS would be the solution I was looking for, but I've hit a problem which I can't seem to unpick.

I've done everything that is set out in the PDFs in terms of installing/uploading, db connection script, setting WA_Globals.php etc, but although I get the splash screen with the login box, after I've logged in, I get a blank page where admin/index.php should be.

I should point out that I've installed this on my testing server (MAMP) as I want to run it first and ensure that I can do what I want with the content of an existing site which I need to convert to CMS for a client, so I've got everything set up in a local folder as normal, with the testing server as localhost:8888/mydomain/CMS/admin/

that's where it's all come to a halt - blank index page so although I'm logged in, I can't do anything and I have no idea where to go from here...