I just did a fresh install of FC6 on my Core 2 duo laptop.

I have not changed any of the repositories. It is a default install.

When I do yum update, I get the following error:

Transaction Check Error: file /usr/share/man/man8/funit-child.8.gz from install of frysk-0.0.1.2006.12.
01.rh1-4.fc6 conflicts with file from package frysk-0.0.1.2006.10.02.rh1-1.fc6
file /usr/share/man/man8/funit-exec.8.gz from install of frysk-0.0.1.2006.12.01.rh1-4.fc6 conflicts wit
h file from package frysk-0.0.1.2006.10.02.rh1-1.fc6
file /usr/share/man/man8/funit-threads.8.gz from install of frysk-0.0.1.2006.12.01.rh1-4.fc6 conflicts
with file from package frysk-0.0.1.2006.10.02.rh1-1.fc6
file /usr/share/man/man8/funit.8.gz from install of frysk-0.0.1.2006.12.01.rh1-4.fc6 conflicts with fil
e from package frysk-0.0.1.2006.10.02.rh1-1.fc6

Can somebody explain to me how to fix this problem?

Thank you.

not sure, but it looks like u have 2 different versions of frysk. Try as root rpm -qa | grep frysk, check out how many versions u have installed and then erase the older one.

When i was using FC5 i faced with same problem.
if your system have a packages different version of i386 and x86_64 and one of them is the last version you live this problem. You have to update the packages which different arch(i386 and x86_64) same version.
i advise you uninstall the packages which are conflicts and install again with yum but don't give reveal architecture write only name of package.
ex:
yum install kdelibs