I repeat the solution as Frans.Linz gave:
"If your pc runs under 2.6.38-9-PAE-kernel, then you have to install linux-headers-generic-pae (eg. with synaptic-packagemanager). The dkms-modules are newly compiled and after a system-restart virtualbox should run."
By the way, I have upgraded from (X)ubuntu 10.10 to (X)ubuntu 11.04 and faced this bug. After this fix virtualbox works again.
I don't know if this is the good place to mention this but the solution offered here (http:// ubuntuforums. org/showthread. php?t=1747766) helped me.
I repeat the solution as Frans.Linz gave: 9-PAE-kernel, then you have to install linux-headers- generic- pae (eg. with synaptic- packagemanager) . The dkms-modules are newly compiled and after a system-restart virtualbox should run."
"If your pc runs under 2.6.38-
By the way, I have upgraded from (X)ubuntu 10.10 to (X)ubuntu 11.04 and faced this bug. After this fix virtualbox works again.
Huseyin