Getting back to 9.8.0.0

I'm stuck with 9.8.0.1: when using Install New Software to apply the
9.8.0.2 fixpack so I can get to 9.8.0.3 or doing Check for Updates, I get
nothing or an error
(An error occurred while configuring the installed items
session context was:(profile=profile,
phase=org.eclipse.equinox.internal.p2.engine.phases.Configure, operand=null
--> [R]com.ibm.rdi.acs.update 9.8.1.202312011900,
action=org.eclipse.equinox.internal.p2.touchpoint.natives.actions.CopyAction).
I/O Error while copying C:\Program Files (x86)\RDi\windows\IBM Rational
Developer for
i\plugins\com.ibm.rdi.acs.update_9.8.1.202312011900\bin\acsbundle.jar - see
details.
Error while copying: C:\Program Files (x86)\RDi\windows\IBM Rational
Developer for
i\plugins\com.ibm.rdi.acs.update_9.8.1.202312011900\bin\acsbundle.jar).

ACS 1.1.9.5 works fine. So, I'll go back to the RDi initial release and
work from there.

The question: should I uninstall RDi completely before reinstalling or can
I install from the 9.8.0.0 archive on top of what's there?