Multiple, non-clustered LiveCycle instances against a single database is neither tested, nor supported. For each instance, you'd need a separate database (with multiple sets of tables, views and sequences). All changes have to be repeated for every instance you have.
This technical whitepaper from Adobe will provide more details:
http://www.adobe.com/devnet/livecycle/pdfs/lc_platchoice_wp_ue.pdfWhat you are attempting is a deployment architecture the author of this whitepaper calls "Server Load Balancing" (see page 11).
You might be better off clustering the three instances.