Avid only supplies AMA plugins for QuickTime and AVCHD and the plugins sometimes need updating with a new version of Media Composer is released  (like version 7). Check to see if you've got the correct Canon plugin via the AMA page that will take you to the Canon site. 

Also, make sure the "Relink by" Source Name is set to Tape Name or Source File Name and "Relink to" is set to Any HD format.

I know I always forget to switch those 2 and it drives me nuts when nothing relinks.  Hope that's it!

Not sure if anyone is still having this problem but I just had this issue with an Avid running 7.0.4 on a Mac, connected to an Editshare.

I couldn't link to AMA on any kind of file, locally or on the Editshare. None of our other suites had any problems.

The solution was to remove (I actually just renamed, to hide them from Avid) the Users\Shared\AvidMediaComposer\AMA Management\Ama Metadata Folders and also the Managed AMA Media Folders.xml

I'm not sure if it was just one of these, or perhaps the XML file had gotten corrupt somehow. But anyway, getting rid of these so Avid had to recreate new ones fixed the problem.

I'm also not totally sure what the ramifications of doing this is. On another thread I read that I might lose some of the metadata information for clips that have been loaded with AMA. Which might not be a problem since our general workflow is to consolidate/transcode clips once they're loaded up. But if I had a different workflow with the AMA clips (creating lo-res proxies and then re-linking back the AMA clips for example) then possibly this would be a problem. I'd love to find out more.

In the meantime I'm glad to have found a solution!

cheers

Campbell