You really have my sympathies.  I'm in the process this very second of patching my new installation of "Neverwinter Nights 2: The Mask of the Betrayer" expansion pack.  (Yes, seriously!!) Awesome game.

That file is critical for Microsoft's application compatibility and might have become corrupted.  Were any Windows updated installed recently?  Removing update KB935280 has been known to resolve problems with this DLL, but that's for Vista, not XP.  

That's an old version of aclayers.  The newest one is 6.1 or something like that.  Are you running Service Pack 2?  It might contain the newer version.  If need be, try downloading a newer version of aclayers.dll from one of the sites that provide Windows DLLs.  Just be warned that I can't vouch for the safety of any of these links.

http://www.dlldump.com/download-dll-files_new.php/dllfiles/A/aclayers.dll/6,0,1,135f/download.html

http://www.driverskit.com/dll/aclayers.dll/1.html

http://www.afreedll.com/dll/info/aclayers_dll.html

Do a search on your hard drive. It should be in C:\Windows\System32, but it could be elsewhere as well.  If there are multiple copies, remove or rename any older ones.  (Just look at the date on the files.)

The DLL in question deals with application compatibility, and NWN is an older game, but I don't see why that would be causing a problem.  NWN2 completely blows the original away; however, its system requirements are much steeper.  You might not be abe to get a satifcatory experience with your laptop.

Also make sure that ALL of your laptop drivers (chipset, video, audio) are up-to-date and that your version of XP is at least Service Pack 2