The most likely cause for this is that the site is on an address that isn't trusted. Internet Explorer opens sites in zones, and it may have put your development address in an untrusted zone, which disables scripts by default. You can usually see an icon somewhere that indicates this and allows you to add the address to the trusted zone.
Look for an eye icon or a warning icon - depending on the version of Internet Explorer you are using.
You could also fire up another browser and see if it is any different.