Last I heard, all recent versions of Daemon Tools have a rootkit that installs on your system. It doesn't do anything malicious; it just hides DT from copy protection schemes like SecuROM and StarForce. Apparently, if those schemes detect DT on your system (and they do actually check your system, both on install and at run), then it will prevent you from running the protected program.
My main concern is that while the rootkit doesn't do anything malicious directly, it can be exploited by other malicious software. If that happens, you're in deep trouble, as you can't be sure the machine is actually doing what you tell it, i.e.: when you scan for viruses, your system may come up clean, even if it is infested, because the rootkit is masking the presence of the viral infections.
