Are you printing to a network printer? It sounds very much like there is some network or network configuration problem on that computer. CardExchange reconnects for every query, so it seems the network gets blocked somehow by the action of printing.
Cannot read data from [database].
A network-related or instance specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provide: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server).