Telnet into your dm500 and type ps then hit Enter. Do you see CCcam listed as a running process?
Linux is case-senstive and the cam must be named CCcam (and be in /var/bin/emu) else it won't be detected by the Softcam menu. But I guess this can't apply to you, otherwise you wouldn't be seeing it as active in that menu.
Which leaves one other possible culprit: You have /var/etc/cccam.cfg instead of CCcam.cfg
2.2.1 works rock solid for me in all versions of dm500 Commando so far, when tested for educational puposes