Take the cartridge out of the printer. Check to see if the label paper is not sticking out too much or not sucked in too deep. If sticking out too much push it back in gently till it is in align with the opening of the green plastic part of the cartridge. If it is in too deep try pulling it out till it is in align with the opening of the green plastic part of the cartridge. This will make it easier for the printer to roll and communicate with the software. If this is not the case then proceed to update your firmware to latest version on the Leitz site.
Also make sure the print button is green and not greyed out. If the Icon is offline software will not be able to read the cartridge information. In this case this would be a offline problem of the printer and not a cartridge problem.
This could also be resolved by performing a power cycle. ( take the power plug out wait a few secs and insert it back in).