monitor goes to sleep while install RHEL 5.1

[Chris Henderson <henders254 gmail com>]

When I try to install RHEL 5.1, I get "input signal out of range" and
the monitor goes to sleep. When booting off the install DVD, I execute
"linux resolution 1280x1024" from the command prompt (without the
quote) - but this doesn't help and the monitor still goes to sleep.

How to fix this issue?

Thanks.