Linux Debian Kernel sources missing error.

hi
please help .Someone can have experience to resolve this error or to give a quick answer to help me because
Parallels Tools upgrade in Debian virtual machine fails with error and the message was like this "
"An error occured when downloading components for building Parallels Tools kernel modules – kernel sources. Install these components and try again":
im waiting for you thanks

Error:
An error occured when downloading components for building Parallels Tools kernel modules – kernel sources. Install these components and try again
