This has been observed only with the ServiceLedger customer portal. The cause is installation of the ServiceLedger customer portal before installion of .Net 1.1 which the customer portal uses. To correct:
- Log in to your web server as an administrator (local or domain)
- Go to Start->Control Panel->Administrative Tools->Internet Information Services
- Expand the web server (local computer)
- Expand Web Sites
- Expand Default Web Site
- Select SLCustomerPortal, and right click
- Select Properties from the pop up menu
- Locate and select the Documents tab
- Click Add..
- Enter default.aspx and click OK
- Click OK
- Close Internet Information Services window
- Reboot your web server
Another issue may be resolved by selecting "Scripts Only" for Execute Permissions on the Virtual Directory tab you see in step 7 above.