Thanks for your reply. The problem is, I now am unable to login to my site's backend... correction, I can login but the backend's index page is the one giving out the 2nd error I pasted above, so no site control panel.
Edit: right, managed to get to the components page and reinstall it, which fixed the problem, so thanks for the suggestion. However I got lucky because I had the url in my browser history. MobileJoomla if you don't mind me saying, should be able to exit elegantly from a failed update instead of bringing the whole site down.
In any case, thanks for your work on MobileJoomla, I like it