Importance:
AWA
AWA reponds to a member who received an error.
AdWordsAdvisor Says: [
Link to quote]
mahlon, no limit to the number of campaigns you can start in one day (well, up to 25 total at any rate...), so that won't be the issue.
My guess is that this would have been a temporary problem, and that trying again in 10 minutes would have 'fixed' it.
Also, I have learned over time that re-booting my computer seems to resolve about 95% of all issues. It is almost like magic or something. So I would suggest a re-boot, should this happen again. At the very least, try a new browser window.