Interesting...
Are you trying to play multiple games at once? I do this with no problems, although I can only put out 5 seeks at once. You are a premium member, so you're allowed this.
Otherwise, it's probably a glitch - I've never heard of this before.
I keep getting "no new seeks while playing" when my opponent refuses a challenge. Even after I ask more than twice & get "challenge.failed" I cannot request a new game. What is going on here?