The number of reasons that make your battery drain so quick could be unlimited: bugs, bad installation, compatibility, etc. You can disable Polaris Viewer from Menu > Settings > Manage Applications > Polaris Viewer > Force Stop and the application will be stopped until the next phone restart. You can permanently disable it using an application like Titanium Backup but that involves in rooting your device. If you stop Polaris Viewer you will not be able to view documents anymore.
