If it is a tarball of a working filesystem (ie: the files themselves), (i really dont see anybody providing this, when my latter suggestion is more suitable, but i digress), you would need to replicate the partitions and disk structure completely. You mention creating ext2 and ext3 partitions, this is unclear as to whether you created filesystems as well. Also, you don't mention installing a boot loader.
I would imagine it is more likely to be a disk image, ie: VDI type file. Where you would need to create a virtual machine, and then tell it to use the disk image included in the tarball. I don't use vmplayer so I cant be of much help with doing this.
If this doesn't help you perhaps posting (as an attachment) a listing of the tarball may help people see whats going on.
Code:
# tar -tf /path/to/tarball > tar_listing.txt
How does it "not boot", what error are you getting?