I am getting this error logged for browscap.module, line 392 or 397.
Checking function browscap_get_browser(), I've noticed that the only return clause (return $info;) is conditional. I suppose this can be the reason that in certain circumstances this function doesn't return an object, as expected in lines 392 and 397.
So, I believe we should:
1. ensure the returned value of browscap_get_browser() function is always an object (so we can be sure $browser in lines after 391 is always an object), or
2. check if $browser is an object or not after browscap_get_browser() call (in line 391)