R omnetpp-package cannot be loaded

[rickywcs]

platform : win 7
R : R-2.12.2

I try to install the omnetpp R package , but it fails.
How I can do it ..

On Windows, download the zip file instead of the tar.gz one, and choose “Packages > Install packages from local zip files…” from the menu.

utils:::menuInstallLocal()
package 'omnetpp' successfully unpacked and MD5 sums checked
require(omnetpp)
Loading required package: omnetpp
Failed with error: ‘package 'omnetpp' is not installed for 'arch=i386'’
local({pkg <- select.list(sort(.packages(all.available = TRUE)),graphics=TRUE)

• if(nchar(pkg)) library(pkg, character.only=TRUE)})
  Error: package 'omnetpp' is not installed for 'arch=i386'
  #########################
  It means it has installed or not , or It needs MD5 sums checked ? But I type the MD5 sums checked , it also failed.

How I can do it?
Rgds
Ricky.