Using explorer, browse to your Bitweaver install directory
Right-click on the temp directory
Select Properties
Select the Security tab
Click Add and add the IIS user (mentioned in the error page above); for example IUSR_xxxxxxx
Then check the Modify rights checkbox
Press OK to apply changes
Repeat the above procedure for the storage directory
Create an empty text file called kernel/config_inc.php and repeat the above procedure to assign Modify rights to is also.
At this point, revisit your homepage http://localhost/bitweaver and you should get redirected to the installer
If you're using MS-SQL or MSDE, refer to the SetupMSSQL page
Note: If your using IIS 3.0 and there are some unuseual directory names (in one case the extra directory was named: _vti_cnf ) it could be that you need to remove the Frontpage Server Extensions. This is described at http://support.microsoft.com/kb/q244221/