Gkrellm fails to detect a running mbmon daemon on amd64. There is a "#if defined(__i386__)"-block at lines 198-237 in src/sysdeps/sensors-common.c, which prevents the code for detecting mbmon-daemon from being compiled in gkrellm at least in amd64. (Actually, i don't see why the mbmon-detection is restricted to i386) As i'm using amd64 only, i just stripped the #ifdef away, as i don't know what symbol amd64-platforms define for the purpose (Googled, could it be __x86_64__?), but the solution would be to append the correct "|| defined()" to the end of line 198. (Or to remove the whole #ifdef, if it isn't needed)
Fixed in CVS, mbmon support works fine on amd64 - suggested the same change to upstream in addition. Thanks Aleksi.