Try "rundll32.exe shell32.dll,Control_RunDLL" in Start->Run, this is another way to open control panel.
It is really strange that issue only happened in safe mode but not in normal mode. In normal mode windows will load driver of network, video, sound etc. In safe mode they don't be. If some problem has happened with the original system files of OS, it will be replaced by other good file in normal mode. Maybe it can explain why it only happened in safe mode. I just guess that. So you'd better follow some steps to check .cpl and control.ini files. Here are articles I found from MS KB, some of them are apply with 95/98/Me, but you still can try with yours.
How to Troubleshoot Control Panel Issues in Windows
http://support.microsoft.com/?kbid=299923&sd=RMVP
Control Panel Does Not Open
http://support.microsoft.com/?kbid=221153&sd=RMVP
Control Panel stops responding in Windows XP
http://support.microsoft.com/default.aspx?scid=kb;en-us;843551