zlplayer9911 ,
You have to choose old workspace and MyEclipse will find old drivers.We add a lot features and fixes in MyEclipse 4.1.1 and please, use this version.You will have to reconfigure driver (maybe), because we add some changes in connection and driver definition.
If you reinstall same version and choose same workspace you have to find correctdriver definition.You have remove workspace (or you have broken workspace)
Thanks