What do you mean by “importing using the media tool”? The only time you import in Avid is when your choose File–>Import. This takes the file you choose and converts it to an OMF or MXF format, which Avid then puts into its media folders.
If you’re trying to use the Media Tool to “import” masterclips you should choose to show only the MasterClips in the Media tool option. Then just select the ones you want when Avid is done loading them and drag them to your bin.
If you’re trying to import an MXF file you might have problems. Typically you just drop the MXF file into Avids media folder, then use the media tool to show the masterclips.
If you’re starting Avid and it’s giving you this error then you have corrupt media.
Give us some more details about what exactly you’re trying to do, the steps you’re taking, and when the error message appears. And system specs would be good too, including the version of Avid you’re running.
Thanks,
Michael.