Unable to launch C:/Program Files/Sony Online Entertainment/Installed Games/EverQuest II/EverQuest2.exe - 193: %1 is not a valid Win32 application.
Have you recently come back to the game? Having the game installed in Program Files can cause problems. I suggest you move the entire game folder to a custom folder or just on the root of the c: drive and then try the patcher. If you would rather reinstall the game the launcher should choose a folder other than program files by default. If you do, just stop the install after a few minutes and copy the paks and music folder out of the old location and into the new folder to save download time. Really not much else to suggest until you move the game folder.
To save having to click through a page or 2, a direct link to the installer: https://launch.daybreakgames.com/installer/EQ2_setup.exe
eq2 doesnt support XP anymore http://eq2wire.com/2016/05/20/eq2-official-support-for-windows-xpvista-ending-in-june-2016/