I believe Mandrake 10.0 comes with 2.6.5 or something later, so you should be fine.
"Required kernel" doesn't mean anything other than what it says - it's basically the version # of the kernel that is necessary for whatever function is telling you that.
Edited to add: You don't need to install the kernal source or compile a new kernel unless you want to upgrade. There are several guides out there on how to do this, including one here: http://www.linuxquestions.org/questi...threadid=73436
but keep in mind it's slightly different for 2.4.x and 2.6.x kernels; those directions appear to be for 2.4.x.