algor: that's a bit few info, isn't it?! none can help with that 
anyways, same problem here. but to be precise: the drivers DO compile, but insmod fails:
	Code:
	     Compiling Parallels Workstation 2.1 drivers...
     Drivers have been compiled successfully.
     Installing drivers...
     Starting drivers...
hex: start offset no good
Loading Parallels Workstation 2.1 hypervisor ...
Loading Parallels Workstation 2.1 vm-main ...
insmod: error inserting '/usr/lib/parallels/drivers/drv_main/vm-main.o': -1 Operation not permitted
 Can not load vm-main module.
Parallels Workstation drivers were successfully configured
and compiled but cannot be started (insmod command failed).
Run 'dmesg' command for more information.
 dmesg spits out this:
	Code:
	[29822] Device /dev/hypervisor registered with 10.60
[29822] parallels Hypervisor 2.1-1670 initialized.
[29831] No salt specified! (/usr/lib/parallels/drivers/drv_main/vmmain.c:55)
 the hypervisor.o loaded fine.