Got a weird issue here! I have a trial version of delphi 2009 installed and have 30 days left on it. I have installed TsiLang 6.4 in to it and am trying to play with it but I am getting siComp.dcu not found.
I have created a new simple vcl forms app and have dropped the siLang component on the form. When i then go to run the form, i get a "siComp.dcu not found" error.
I don't know if Trial version of Delphi 2009 allows using of 3rd party VCL. But I guess you can try to edit Library Paths settings in Delphi 2009 Environment option to check it includes the folder where siComp.dcu for Delphi 2009 is placed.