Audio clips causing IE freeze

I have several courses that contain .mp3 and .wav audio clips. They have worked fine for over a year but have suddenly broken on some PCs. The only difference between working and non-working PCs is the IE version. 6.0.2900.2180.xpsp_sp2_gdr.070227-_2254_ is fine. Anyone with 6.0.2900.2180.xpsp_sp2_qfe.070227-_2300_ has a problem. The symptoms are a complete IE lockup.I found that gdr and qfe represent different branches of Windows Updates. QFE has more 'engineering' fixes, whatever that means. Nobody knows why some machines have one branch vs. another. Every machine is managed interally through the same SMS rules.To further confound the issue, I discovered that when publishing to HTML and previewing locally, the course works fine. When published to SCORM 1.2 and ran from an LMS, the course freezes. LMS: Saba Enterprise 5.4SP2IDE: Saba Publisher 5.1.wav and .mp3 filenames are only alphanumeric, with no spaces.Any ideas, help, or suggestions are greatly appreciated. Many thanks in advance.