The following was posted by Roy Nelson as a way to get Delphi 8 back up and going with .NET 1.1 SP1. Please note that this is a “shotgun” fix and has not been verified by Borland QA, so your mileage may vary:
1) delete all *.dc* (BUT just make a copy of your $(BDS)lib BEFORE deleting all the *.dc* files)in the $(BDS)lib dir and $(BDS)libdebug dir (do not touch the other files eg. .resource, .res and .nfm files)
2) go to the $(BDS)source dir and run the makefile file with "default" and "debug" options.
So from command prompt in the $(BDS)source dir you run
"make default debug" (without the quotes)
3) delete all old *.dc* in you project dir and re-build.
4) in VCL projects you might still see issues but all you need to do is remove the references to the VCL assemblies in the project pane and then do a re-build of the project.
5) if you still see any compiler error, either remove the offending assembley from the references and do a re-build.