TRichView.com

If we enable the language property by editing RV_Defs.inc {$DEFINE RVLANGUAGEPROPERTY} the richviewactionsd2009.bpl will not install anymore. Entrypoint procedure not found in RVPkgD2009.bpl

Recompile the RichViewActions package.

I have first uninstall packages rvpkgd2009, rvdbpkgD2009 and richviewactionsd2009.
Then rebuild all the 3 packages
Install packages. The richviewactionsd2009 gives error about entrypoint.
Then uninstall the packages, close delphi 2009. Delete packages cache in registry of windows.
Start Delphi 2009 and rebuild and install the packages. Still same error

Probably you have copies of compiled packages (*.bpl and *.dcp) in some other directories, and Delphi tries to use them...

With D2006 it works fine. D2009 problem still exitsts

The only possible reason of "entry point" error is mismatched versions of (compiled) packages.

I have remove everthing. Registry items, D2006, richview and richview actions. Remove component, .bpl, .dcp and still get the error.
All package are in the same directory.
If language property is set than richviewactions will not install

I am sorry, I cannot reproduce this problem. When I enable this property and recompile RVPkgD2009.dproj, all other packages (including RichViewActions) requiring this package show error message about entry points or like this. It is expected. After recompiling these packages, the error is gone.

In Delphi 2009 by Tools | Options | Environment options | Delphi Options | Library - Win32 there was an wrong directory added.
Removing this item fixed the problem