Try this in a terminal.
It should say that there is no alias for more. If there is an alias then that could be the problem.
If that doesn't help then try this in a terminal window.
That should point to /bin/more or /usr/bin/more. Then make sure that this file is the correct one by determining the file type as follows:
Substitute the actual path to more on your system. The file command should return the following:
/bin/more: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked (uses shared libs), stripped