Help please-installed but not working

[hel]

Hi, I hope someone will be kind enough to help me.
I have installed coppermine (on yahoo hosting)....I read the coppermine + yahoo hosting thread and did what was on there. I believe it installed fine, it said it was installed and then when it redirected to the login and also the admin page the page was just blank.
I have installed Coppermine on a non yahoo host with no problems so I am at a loss as to what to do now.
I'd appreciate any help as I just paid a lot of money for webspace and really, really want Coppermine on there!
Thank you in advance

[Paver]

Have you tried running the installer again?  It will probably say the installation has been locked, but might as well check.

A link to your site might be useful.

[hel]

Yes, I deleted the locking file and reinstalled it but still have the same problem.
The gallery is www.chasingtails.net/gallery
Thank you

[Paver]

My guess is that your themes folder is not readable by all (or is missing).  All the pages that use the theme (classic by default) show a blank page.  The pages that don't come up fine.

[hel]

Thanks for your help
By my themes are not readable.....does that mean the permissions are not set to 777? I checked and all the theme folders are set to 777. This is driving me mad 
Any other ideas please!!!