Based on the "Unknown database 'DS2'" message, you need to make sure that you followed the instructions in the "Prepare the DVD Store 2 Database" section. Although you used the templates, they still require some configuration by users prior to use. This may also be the cause of the issues found in your DS2Web wrf files, but I'd also double check you've setup the hosts files in your DS2Web VMs to correctly point to your DS2DB VMs. For more information, please see the troubleshooting/configuration sections of the benchmarking guide.
Finally, the "ERROR -- Caught exception SwordfishExceptionTooMuchLoad:Number of unfinished tasks including those in the queue and those are being executed is greater than 1.5 times the number of users." Is usually an indication that the storage configured for this workload is not able to keep up with the demands of the application and as a result Loadgen has crashed. There are several threads in this forum on the topic that should be most helpful in helping your isolate, identify and work around the issue.