It sounds like it's unrelated to Forms Viewer. I haven't encountered the first error you mention, but the second error sounds like an error when DBXL is trying to modify permissions, probably related to the SQL instance.
Here is the sequence of events when DBXL installs, which might help us to narrow down the problem: database connection tested, web.config is created, Qdabra event log is created, registering with ASP, checking for Sharepoint, installing for Sharepoint (if present), QdabrawebService, Database creation, Trial License installation, Admin Tool published. During the initialization of the installation, the installer tests the creation of the databases QdabraSamples and QdabraDBXL.
Are there are errors or warnings in eventvwr? I've commonly seen warnings logged when DBXL tries to add a user to the SQL instance.
Ernesto Machado / Software Test and Support ManagerQdabra® Software / Streamline data gathering to turn process into knowledge