The best way to get several (working

) installations is to copy the whole Uru folder after POTS was installed, but before you did any further (community-hacked) patches - this copy then also servers as backup should you break your offline or Shard installation.
http://www.guildofwriters.com/wiki/TPOTS_Installation describes how you could get such an installation. If you copy an existing installation, be aware that some old patches might be carried over that the Shard or new patches are not compatible with.