I upgraded my 10.04 system to 10.10 on my way to 11.04. I didn't try VMPlayer on 10.10, but it worked on 10.04.
I tried to start a VM in 11.04, and it prompted me to install the VMWare bits into the kernel. It would fail, and provide a log file. The log file looked normal until the end, at which point it said:
"Failed to compile module vmmon"
I found a number of references on the web for that, but all related to older versions of the kernel. The one I found for 2.6.38-8 was this patch:
but that is for 64 bit. I assume those header patches won't work on 32 bit (yes?)