Another workaround, instead of using Java WebStart, is to use the "open" command with the -n flag. Bring up the Terminal program (via the Finder; go to Application::Utilities). Select Shell->New Window->Basic, and a terminal window will pop up. Assuming the BioTapestry Editor icon is on your desktop, type:
into the terminal. Then type:
open -n 'BioTapestry Editor.app'
hit return, and wait. Do this as many times as you want. Each time will bring up a separate instance of the BioTapestry Editor program.
Sorry for the hackish workaround. We're still looking into the long-term alternatives.