O-DL has very few installation prerequisites, however they are easy to miss, and can lead to installation errors.

If (at runtime) you get an "error - NORESPONSE"  or similar errors that are ajax (JS) related, in the status bar, there could be a couple of reasons and resolutions:

 
1. Please make sure you installed the correct version of O-DL for the DNN istallation you have.  That means that if you are running DNN4.x, you should have installed the O-DL package with DNN4 in the name.  For DNN3.x installations there is a corresponding package with DNN3 in the name.
 

2. This applies to DNN 4.x only. 

In DNN4.x you can change a number of settings that are known as performance settings.

Go to Host/Host Settings expand the Advanced Settings and the Compression Settings sections

Of this family of settings, there are two in particular that need special attention.

The setting known as "Page State Persistance" must be set to Page, otherwise it will break O-DL

The setting known as "Compression Setting" if set to anything other than "No Compression", needs an extra parameter to be added in the exclusion path.  If, for example, you were to set compression to "GZip Compression", then you would have to

Note:  The above has been tested on DNN4.8.  It may not work on previous versions, so please just disable compression if adding the exclusion path does not work.

• Go to Host/Host Settings
• expand the Advanced Settings and the Compression Settings sections
• in the "excluded paths" text area, add tabid=xx (where xx is the tabid where odl is installed)
• click on the update link for that section, not the general update that is at the bottom of the page.