Had the same problem. Read a lot on this blog and was impressed by the comment that FlyInside doesn't work with X-Plane 11.10 and we would have to wait for their update. Also, not possible online to go back to a prior version of X-Plane. Very discouraging, but I fortunately had purchased a set of DVDs for X-Plane after I had a previous problem with Steam (whence I purchased X-Plane the first time). Steam told me I had to contact Laminar for help; then Laminar said because I had not purchased from them originally, they couldn't help me. I bought the set of DVDs directly from Laminar (paying twice for X-Plane) so I would have an account with Laminar and would get some help.
The point of the above is that I just finished a clean installation of X-Plane 11.0 r1 from the DVDs into a new folder on my desktop, carefully updated the aircraft, scenery, etc. from my original X-Plane folder, and X-Plane launched with no error message. When I launched FlyInside, however, I got the shader error message again. So I re-installed FlyInside from their website (a new, beta version for X-Plane). Voila! I'm flying in VR again.
For anyone who does this, when you launch the earlier version of X-Plane, be careful not to check "update" at the prompt. It will update you back into 11.10 and the problems will start again. Stay with your separate X-Plane 11.0 folder until FlyInside becomes compatible with 11.10 or X-Plane releases their own VR update.
Regarding getting "legacy" DVDs from Laminar, perhaps they will recognize this major roadblock and will sell them at a reasonable price to those who already own their software. Good luck to all with this problem!