Had Orchard CMS working lovely on my local machine (Windows 7 x64) and IIS. I then wanted it moved to my hosted server and once I copied all the files over I found it was erroring. Looking at the Orchard CMS documentation it seemed a few folders needed "Modify" permission. OK this is fairly easy in IIS but how do I do it using my hosted solution. Thankfully the Parallels Plesk Panel (9.5.5 I'm using) had the ability to do it.
Click File Manager
Click Httpdocs (or where you have placed your Orchard CMS files)
Click the padlock next to app_data
Tick the "Replace permission entries on all child objects with entries shown here that apply to child objects.
Tick Modify/ Read & Execute/ List Folder contents/ Read/ Write
Click OK (this might take a while to complete).
You will also need to do the same for the Media/ Modules/ Themes folders.
However I still had issues and found out I needed to give permissions to the "bin" folder too
Just tick Read & Execute/ Read.
Then happily Orchard CMS works perfectly.