The memoQ activation dialog contains a Fingerprint which is related to CAL. When you grant a CAL license to a user or a memoQ serial number, the serial is the fingerprint and give the user a license. The serial number is unique to a user, not the whole serial number is given out, but a fingerprint of this serial number instead. If you have MemoQ support, you should open a ticket. They are usually helpful with technical problems and get the bugs solved. Clearly, something is not working as it should on your computer. Whether it's MemoQ's fault or something else would require some debugging, though.
From Kilgray Translation Technologies: memoQ is an integrated translation environment that boosts the productivity of human translators while maintaining the high quality and increasing the consistency of translated texts. Forget about technical aspects of different file formats, recycle previous translations, and ensure the consistency of your translations with the use of glossaries. memoQ contains a translation memory engine that looks for already translated similar or identical sentences and offers you the translation for editing, a concordance engine that finds all contexts of a word or expression in the history of your translations, a terminology engine that guarantees consistent use of expressions, a very efficient aligner that enables you to build translation memories from files not translated using memoQ and leverage them into new translations, and all these serve you from a single environment. memoQ covers the entire process of human translation, increasing productivity both during the translation work and also during product management.