We are running our own server with Windows Server 2008 R2, the latest versions of IIS, MySQL and PHP. We are having issues with some themes not working properly. Some themes display fine and others its almost like they don't exist and it just displays text. The themes install fine and show the thumbnails and descriptions and you can customize everything just like normal. They just don't display anything from the theme. We have about 3 or 4 installs of concrete5 running on our server and some themes work and some don't. The themes that don't work on our server do work when I upload them and install them on a Bravenet server we have.

Is there an issue with IIS that needs addressed or would switching to Apache be better? We have dug as far as we possibly can trying to get this fixed on the server side and haven't gotten anywhere.

Any thoughts??