IS SQL Reporting services fully up and running? Can you check the status and do all the items have "green ticks".
Also, what about the IIS websites, are they running?
Finally, what ports is EPO using on the server, if it is using the default of 80, then you have an issue as DLP uses 80 too... you can change it in IIS to make it work, but IME, not always successfully.
I just fixed it yesterday by removing DLP completely and reinstalling it. (DLP Server(collector), Report, Tools, ...) The only change I made was that I installed the Event Collector & DLP Report on the SQL server before it was installed on the ePO server.
I installed this with vmware and kept an array of snap shots. I narrowed down my problem (log files) to the credentials being used to start up the reporting services. The manual stated that I use the network service. I was trying to use my domain admin creds. After changing this, the issue was resolved.