This error occurs because you have remaining plugins from RC2 which are not compatible with the current codeblocks.dll.
Go to the plugins folder and look at file creation dates, delete all "old" ones.
EDIT:
Sorry, I did not answer your question "How i am suppoesed to install nightly?" at all...
The correct way to install it is to
- either unpack the archive to a new folder and install MinGW separately
- or unpack to the RC2 folder (if you want to keep the compiler) after deleting the application, the dll, and the shared folder