Http.sys is a Windows file, the scene of the crime.
If it were me, I'd try the registry edit suggested...but lets's try something else first.
Worth reading, http://www.linkroll.com/Operating-Systems-...ptedMmpool.html
What I would suggest is running either sfc /scannow or doing a repair install of XP. A repair install will probably take the same amount of time as running sfc /scannow, but will result in your needing to reinstall critical updates issues since the date the CD used will have been created.
Doing either of these...requires a CD that reflects the same version of XP and at least the same level of SPs installed as your system currently reflects.
How To Use Sfc.exe To Repair System Files - http://www.bleepingcomputer.com/forums/t/43051/how-to-use-sfcexe-to-repair-system-files/
How to Perform a Windows XP Repair Install - http://www.michaelstevenstech.com/XPrepairinstall.htm
OTOH..you can elect to try the registry edit suggested in the analysis you provided. Since this involves editing the registry, the typical caution goes out to you. Editing the registry is something that can produce unwanted effects, so users are requested to back up the registry
before considering such. A good tool for backing up the registry can be found at ERUNT Registry Backup Tool - http://www.snapfiles.com/get/erunt.html
If you are comfortable editing the registry or attempting such, then I would consider that suggestion.