Thank you for the responses. OO works when threads are set to 1024, but anything over that and it fails to launch. No other programs seem affected, so it certainly seems like the crash has to with OO's memory demands.
The book I referred to in my post also states OS/2 supports 4095 threads, with the default being 256 and the recommended first step being to double the original amount--which in my case was 1024. I'm learning more about fine tuning OS/2-eCS settings but don't particularly need to install more RAM.