I met this situation once, but that happen after I installed another company's addon, not CaptainSim 757 pro.
after I install the addon and run fly, the addon fail to load 2D cockpit correctly. I can fly it in the cockpit without some gauges but the same red lines always on the up left corner on my screen. even I restart FSX. Then I restart my computer and reinstall my computer drivers. the red lines dispeared.  Till now, I still don't know what happen and which of my steps resolved the problem. maybe differnt display settings will help?
still a question