hi all.
my problem is when i run command "yum install heartbeat",
the output i get is:

Setting up Install Process
Setting up repositories
http://download.fedora.redhat.com/pu...ta/repomd.xml: [Errno 4] IOError: HTTP Error 404: Date: Wed, 20 May 2009 07:51:05 GMT
Server: Apache
Content-Length: 254
Content-Type: text/html; charset=iso-8859-1
Trying other mirror.
updates-released 100% |=========================| 951 B 00:00
http://download.fedora.redhat.com/pu...ta/repomd.xml: [Errno 4] IOError: HTTP Error 404: Date: Wed, 20 May 2009 07:51:14 GMT
Server: Apache
Content-Length: 248
Content-Type: text/html; charset=iso-8859-1
Trying other mirror.
Cannot open/read repomd.xml file for repository: extras
failure: repodata/repomd.xml from extras: [Errno 256] No more mirrors to try.

any of u know how to solve this problem?
thanks in advance.

Likely because there is no Fedora Core 4 repository any longer. They're up to version 10 and have dropped support for version 8.

Fedora is bleeding edge and updates versions very frequently. Even if it weren't FC4 would still be pretty old as distros go.

From the Fedora Overview page at:
http://fedoraproject.org/wiki/Overview

You should probably upgrade your system. If the once a year stuff above is too much for you then you might want to consider using RHEL (commercial) or CentOS (non-commercial) version 5.3 - These latter are not quite a bleeding edge. Fedora is used as a testbed for what ends up in RHEL (and then in CentOS).

Fedora 4 support ended many YEARS ago
install fedora 10
or this thread may help - it is for fedora 6 but....
http://forums.fedoraforum.org/showthread.php?t=221471

and only some of the software is in the archives