Stefan,
You are missing some steps before you can boot the NetApp Simulator. Search the web. The VMDK files are in the wrong format for VMware. There is a long process to get this sim working.
Some of the steps you need are below.
Not my work, copied from other places:
# vmkload_mod multiextent
Disk changes made:
/vsim_esx-7m # vmkfstools -i DataONTAP-sim.vmdk DataONTAP-new-sim.vmdk -d thin
Destination disk format: VMFS thin-provisioned
Cloning disk 'DataONTAP-sim.vmdk'...
Clone: 100% done.
/vsim_esx-7m # mv DataONTAP-sim.vmdk DataONTAP-sim-old.vmdk
/vsim_esx-7m # mv DataONTAP-new-sim.vmdk DataONTAP-sim.vmdk
vsim_esx-7m # vmkload_mod -u multiextent
Module multiextent successfully unloaded
VM powering up!