It installs fine on Linux, on WinXP you need some workarounds:
-[Configure "Build Lazarus"], uncheck [ ]Clean all, uncheck [ ]With Packages, set only to build IDE, nothing else.
-Clean the UIB12\source\lib directory(the .compiled file for full rebuild)
-The icons will not show after installation so i shrinked them to 23x23 Pixels and rebuild registeruib.lrs, they work as .bmp's OR .xpm's (I could send them if you don't know how to make a new .lrs)
-Open the .lpk file from source dir and compile, you should say [YES] to recompile, after that you will get an error, something like "Permission Denied" when linking the executable, that's not a big problem.
-Close Lazarus, open a console, go to the lazarus directory, type "make ide OPT=@idemake.cfg"
-It should compile fine now
-Open Lazarus and start using UIB
-DBGrid has some problems but they might already be solved in the latest CVS