This issue pertains to original LabQuest v1.7 or older or LabQuest 2 v2.1 or older.
Some LabQuests have an incomplete print driver cache caused by an intermittent error during the creation of the cache. This issue was addressed in the 1.7.1 and 2.2 versions of the LabQuest software.
To resolve the issue, update your LabQuest to the latest version of the software: http://www.vernier.com/labquest/updates/
If you are still getting error messages while trying to print, please call Vernier Technical Support at 888-837-6437.