ddice and JSMa, welcome to TikiWiki Community!
About the 'NULL' issue, you are right, there seems to be either NULL or ''. However, it did work for me as is when I packed and tried installing aulawiki 1.6.2 from scratch, as in previous versions of AulaWiki. Maybe that's something relate to specific mysql versions which complain about it? (who knows... for sure not me). SO, just do as JSMa pointed out.
About the other issue, JSMa: I packed aulawiki 1.6.2 on edu.tw.o. I've checked again the file ./Packages/features-aulawiki.info.txt and the line about that menu is updated indeed in there:
INSERT INTO tiki_menus VALUES (100,'Workspace menu','Sample workspace menu','d','');
(note the last ,'' at the end, that you were missing in your line; a new column was added months ago to that mysql table, and the old install file was missing that extra field, even if as empty value)
So for some reason, the file in your server doesn't seem to get updated automatically when you update your aulawiki mod from version whatever (1.6?) to 1.6.2 through the admin interface. This might be a bug in Tiki 2.x Mod feature, if confirmed that this behavior is happening.
I'd wish that some coders could fix that, if so (MangaPowerX, can you or anyone else in your team have a look at that? If too busy still nowadays, maybe at the TikiFestMadrid we can test it again and fix it ;-) ?
HTH, and welcome to test and use AulaWiki, ddice and JSMa. If you could help us improving its documentation, your help would be very welcome (we can discuss how, but I would suggest writing a step-by-step howto from a beginner point of view of AulaWiki usage). Or record a screencast of yourself creating your workspaces, etc. (see examples at TikiMovies using "Wink" program, for instance).
What do you think?