I have been getting the same error ever since Steam pushed the new 1.8.151.7 patch. I kept checking the SKSE page for a new update, but it still says 1.6.4 compatible with 1.8.151.0 for days now. Finally I found this thread and went looking for the Dragon script mentioned here...couldn't find it but opened the SKSE folder inside the Skryim data folder (\Steam\steamapps\common\skyrim\Data), and lo and behold skse.ini was telling it open "TES_.exe". Backed up the skse.ini just in case and changed "TES_.exe" to "TESV.exe" and now I can open SKSE_Loader and GetSKSEVersion shows 1.6.4 and all the scripts are working again!!!! Give this a shot.
