I’ve been trying to help a friend find a fix for two PunkBuster errors affecting his gaming on Battlefield 2 and other games for ages now.  There’s been much searching going on online but now finally it looks like I’ve found some fixes.

MD5 tool mismatch error

I have long suspected that this error was caused by a slight delay in reading the appropriate files from the hard drive.  It takes considerably longer to read files from disk than it does from memory, however there’s only so much memory available in which to store things.

The proof came when I upgraded my friend’s PC from 2Gb of memory to 3Gb and the problem immediately went away.  This means that the game is able to keep more files in memory and so the lag between the file read and the server expecting it is significantly reduced.  Do bear in mind however that this is on a stripped down copy of Windows XP that’s only used for gaming, so you might have to switch lots of memory-hogging programs off before playing.

Service Communication Error

PnkBstrA.exe and PnkBsrtB.exe are known to not run properly on some machines.  There’s a tool available here to determine if these services are working.  Simply allowing these programs through Windows Data Execution Prevention, a system designed to help combat viruses, will fix this.

From the Control Panel, select System (Vista and Windows 7 users will now additionally have to press the Advanced System Settings link) and go to the Advanced tab in the dialog that pops up.  Press the Settings button in the Performance section and click on the Data Execution Prevention tab.

Now you select the option Turn on DEP for all programs and services except those I select and, using the add button, add these two programs to your exceptions list.  This is the same for XP, Vista and Windows 7.

Update

The PnkBstrB.exe fix has proven on my friend’s PC to not be effective long-term after all, if you do have a good fix for this please feel free to feed it back in comments.