Debian unstable is on an older kernel than natty's, so older open-vm-dkms kernel modules can compile. Unfortunately its version is too old and will not compile on natty. The changes cannot be easily cherrypicked because they appear to be intermingled with changes to the user-kernel interface.
Therefore, in the interest of stability, we are requesting the merge of the latest upstream 'git tag'. Several dupes of this bug are posted every week, sometimes several per day. It is possible that there are bugs in the merged code, but as the current package is uninstallable, it seems best to merge the newer release so we can address such bugs.
Binary package hint: open-vm-tools
installing on a freshly built vm, from 2011.02.28 daily build. Installing thru "additional drivers" menu item System->administration-additional drivers
DistroRelease: Ubuntu 11.04
Package: open-vm-dkms 2010.06.16-268169-3ubuntu1
ProcVersionSignature: Ubuntu 2.6.38-5.32-generic 2.6.38-rc6
Uname: Linux 2.6.38-5-generic i686
Date: Tue Mar 1 10:51:45 2011
ErrorMessage: open-vm-tools kernel module failed to build
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Alpha i386 (20110228.1)
Title: package open-vm-dkms 2010.06.16-268169-3ubuntu1 failed to install/upgrade: open-vm-tools kernel module failed to build
UpgradeStatus: No upgrade log present (probably fresh install)