Can’t access install.php. Internal server error

I’ve followed the 5 minute install guide and uploaded/configured everything correctly but when I try to run the install.php I get an internal server error. I’ve looked at the error log and I get this.

[Thu Jun 05 19:01:36 2008] [error] [client 90.196.176.210] File does not exist: /home/tattoosb/public_html/500.shtml
[Thu Jun 05 19:01:36 2008] [error] [client 90.196.176.210] SoftException in Application.cpp:252: File "/home/tattoosb/public_html/wp-admin/install.php" is writeable by group

I have installed wordpress on 3 other occasions with no issues so I’m fairly familiar with the process.

Any help would be great.

Thanks for looking.