ISScript.msi has various problems installing from NTFS partitions if the permissions on the directory containing it aren't what it expects. It sounds odd, but I wasn't able to install it from my desktop, but I copied the file to a Fat32 partition ( too lazy to mess with the permissions issues ) and installed from there. It worked just fine.
Link:
http://groups.google.com/groups?q=is...ftngp04&rnum=1
The bad news is that even though I got isscript.msi installed OK, the LimeWire installer insisted on attempting to download and install it again anyway, which of course failed.