If you have a previous version installed you need to uninstall just the hylafax rpm, nothing else. I use yum...
yum remove hylafax
==============================================================
WARNING: Additional commands may be required after running yum
==============================================================
Loading "installonlyn" plugin
Loading "smeserver" plugin
Loading "fastestmirror" plugin
Loading "protect-packages" plugin
Setting up Remove Process
Resolving Dependencies
--> Populating transaction set with selected packages. Please wait.
---> Package hylafax.i386 20080423:4.4.4-1.el4.sme set to be erased
--> Running transaction check
Setting up repositories
smeaddons 100% |=========================| 1.9 kB 00:00
smeextras 100% |=========================| 1.9 kB 00:00
base 100% |=========================| 1.1 kB 00:00
updates 100% |=========================| 951 B 00:00
smeos 100% |=========================| 1.9 kB 00:00
smeupdates 100% |=========================| 1.9 kB 00:00
Loading mirror speeds from cached hostfile
Reading repository metadata in from local files
Excluding Packages from CentOS - os
Finished
Excluding Packages from CentOS - updates
Finished
Excluding Packages from CentOS - os
Finished
Excluding Packages from CentOS - updates
Finished
--> Processing Dependency: hylafax >= 4.3 for package: smeserver-hylafax
--> Restarting Dependency Resolution with new changes.
--> Populating transaction set with selected packages. Please wait.
---> Package smeserver-hylafax.noarch 0:0.9-6.el4.sme set to be erased
--> Running transaction check
Dependencies Resolved
=============================================================================
Package Arch Version Repository Size
=============================================================================
Removing:
hylafax i386 20080423:4.4.4-1.el4.sme installed 2.7 M
Removing for dependencies:
smeserver-hylafax noarch 0.9-6.el4.sme installed 22 k
Transaction Summary
=============================================================================
Install 0 Package(s)
Update 0 Package(s)
Remove 2 Package(s)
@chaloner: what has to be uninstalled? Only the hylafax-rpm or also the dependency smeserver-hylafax? Could you advise please?Thank you.