Not really, but sometimes I get an error from Hammer and it shuts down.
But that's like 4 times a year. Sometimes I get a message, like: Couldn't find OpenGL Driver. But that's only when I shut down Hammer.
Well your problem sounds strange, I don't think it's the RAM, cause I used Hammer on my old PC (100Mhz, 8Mb RAM). Except that it went a bit slow. (Hmmm...a bit?)