Why is it silly that the record and playback sample rate have to match? If you think about it, when you're recording, the sound you're listening to is looped through your sound interface. If the rates don't match, it'll stop working because from your description, you're probably using something like a simple Realtek which can only do one thing at a time.
Really, the inbuilt sound cards on most computers are NOT designed for any serious recording--they're far more suitable just for watching Youtube or making Skype calls. However, you CAN use it if your really must--but it'll get confused trying to handle two sample rates at once.
It's not anything silly in Audition--it's a limitation of your sound card and operating system.
/avatar/30.png?a=8683){kind=small}
