1. The EigerPAY MSI contains a separate MSI (DigitalPersona Gold Fingerprint Recognition SW for Java 2.5.0) which is executed during EigerPAY's install process. As part of that sub-install, it installs and attempts to start a service called 'User Authentication Manager'. Although the service installs, it fails to start under a Group Policy-driven install, stating that the account used has insufficient privileges. Bearing in mind that Group Policy-driven installs do so using the local workstation's System account, it's hard to know how much more privileged an account needs to be.
Anyway, it turns out that the Digital Fingerprint is an optional, paid-for add-on so it should be installable as a separate feature (I have advised Eiger of this) but, for now, I commented-out the call to the MSI.
2. The software has no backward JRE compatibility: it explicitly checks for v1.4 and will use nothing else. If you have 1.5 or above, tough: you'll need to install 1.4 AND set it as the default. This will neatly break your apps which require greater than 1.4 unless your user(s) remember to change the default back again.