In my mappings the special characters like <CR> are not recognized.

How can I configure Vim to recognize special characters? Check the value of the ‘cpoptions’ option:

    :set cpoptions?

If this option contains the ‘<’ flag, then special characters will not be recognized in mappings. Remove the ‘<’ flag from ‘cpoptions’ option:

    :set cpo-=<

Also, check the value of the ‘compatible’ option:

    :set compatible?

The ‘compatible’ option must be reset:

    :set nocompatible