This is a known issue with HTDM plug-ins on Win XP only and has been fixed in Pro Tools 6.4cs11 and 6.7cs3.

Note - Most HTDM plug-ins are not labeled as HTDM, rather just TDM. Waves 5.0 does differentiate between TDM and HTDM in the plug-in pull down menu. While Digidesign expects that this issue effects all HTDM plug-ins on Win XP, we have confirmed that the problem occurs with Bomb Factory: Essential Tuner, Funk Masterizer, Stereo Correlation, Noise Meter, Meter Bridge, and Cosmonaut Voice. Also, Digidesign Long Delay.