Some advertisers have a limit on the amount of keywords you can have per account. Is there one for adwords account?
I've been told by my AdWords rep there's a limit to the size of the account - and that account size could be exceeded by keywords, ads or other elements of the account.
50,000 keywords per account. 25 campaigns per account. 2,000 keywords per adgroup. Not sure of any adgroup limits...
I believe that this can be manually overridden by an Adwords account rep, hopefully all you have to do is ask.