A basic cursor problem

Good evening to all,

I use xemacs to type my university reports using miktex, and while
typing the source code, the cursor is always moving upwards or downwards
for more that one line, it's 4 or 5 actually. This is annoying, and as I
was told that xemacs is fully customizable, I wonder if a good soul
could tell me how to fix this problem. I do not think it is a major
problem, but rather a question of a beginner.

Thanks.

Jined.