I took a quick look at the IBM web page and it looks like the server you got has a 32-bit CPU, which - unless I'm mistaken - will prevent you from running 64-bit guests. In order to run 64-bit guests you need a 64-bit CPU with VT-x.
As for the virtual disk, please attach the virtual disk's descriptor file to a reply post. You can download this file either by using e.g. WinSCP or by starting to download the .vmdk file from the datastore browser and canceling the download as soon as the small descriptor .vmdk file has been downloaded. Each virtual disk consists of two files, the descriptor and the data file. However, these files show up as one single file in the Datastore Browser.
André