Display suite 7.x-2.4, Drupal 7.22
The error message you quote has nothing to do with Display Suite.  It is caused by a bug in the Link module (as should be obvious from the error message you quote).

Here is a link to the relevant issue ticket.  If you read through the long list of messages, you'll see that the fix for this bug was commited to the dev branch of the Link module on May 23 2013. It is not in the "recommended" release.  The "recommended" release of the Link module is from February 9 2013, so it is quite old.

Try to install the dev branch of the Link module, and see if things improve.