I had SP3 installed on my PC. But there was no SP3 CD. So had some trouble installing IIS and other win components. So I obtained a SP3 EXE. It took half an hour to install, but it installed without errors.
When I went to add/remove components to install IIS, I got the error:
Setup was unable to open information file fp40ext.inf
This was followed by some 'error 0x2'. Looked up on the net and found some good pointers.
fp40ext.inf is a FrontPage extension info file. It was missing from the C:\Windows\inf folder. I copied it to this folder from C:\ServicePackFiles\i386 folder. Then I got the error fp40ext.dll was not found. Copied this file too from ServicePackFiles to the c:\windows\system32 folder. Then I got the error about missing pinball*.inf file. Taking cue from a website, I opened the sysoc.inf file and commented the line for pinball, using ';' character. Also commented the line for msnmsn (the next error source).
After this, the add/remove component dialog box opened, I was able to install IIS (except for the file admxprox.dll which I got from Xp-SP2 CD) successfully.