Doesn't seem to happen when I'm elsewhere on the site, but if I'm on the main Assets (Browse Assets) page, and try to use the Search Box up top, it comes back with this at me:
Tried it while on several other pages on the site, and no trouble, so, not impeding me lol. But thought I'd let you know. 
Thanks for the error report... I'm not experiencing this, and I think it may just be an issue with your browser caching... have you tried clicking on the "reload this page" link, and then searching again?
Is anyone else experiencing this error?
I tried just to see and it happened to me too just the way Melissa said...
I clicked on assets and while on browse assets page, I did a search for "stripes" and got the error.
...now that it's a few days later and I tried again, I'm actually not seeing this problem anymore! I haven't cleared my browser cache or anything since then - and reloading the same page that day didn't resolve the issue, I did try a few times. But, whatever it was, has since stopped. hmm. (FWIW, running the latest version of Chrome as my browser.)
@Melissa: I just did the same search again and it has stopped happening to me, too.
without clearing my cache either.
Thanks for the update, ladies.
If anyone experiences this problem again, please let us know.