Im trying to install slackware on VMware from WinXP (its my wife's computer.. going this route to try and get her to switch

)
however.. I cannot at all get this thing to run setup... it says there are no partitions. If i run cfdisk of fdisk.. is says the disk could not be opened?? Any ideas?
I can get mandrake to install (useing the auto partition).. but i want slackware.. Why cant I fdisk with slackware?
any ideas?
Thanks
trey