If the dreaming prison is the last instance you went in,then,it was just after defeating Akhenaton,did you try to go back the Akhenaton’s place?If u can’t,try to go back at every stages of the story quest before the dreaming prison Aka: https://www.ign.com/wikis/the-secret-world/Black_Sun,_Red_Sand
Also,even if you reinstall the game,some files still remain because they are not with the others files of the game,go to users>user>app data>local>funcom>delete the whole funcom thing don’t worry as i said,the game will remake them by it’s sell when you will loggin)