Thank you for your reaction.
This solution works only with Adobe premiere Elements 11. I have Adobe premiere Elements 10.
I have tried, but it doesn't work. When I use this fix, the progam doesn't start. It gives a window with "the progam doesn't work, ask your adminostrator'
About a year ago I worked with a Premiere Elements 10 Mac user at a forum that I no longer visit. Same Timeline zoom issue. We tried several approaches including the one that works for Premiere Elements 11 Mac. Unfortunately, nothing worked to correct the problem in version 10 Mac. The user eventually went on to Premiere Elements 11 or 12 Mac.
But, just in case, have you checked the program's preferences for one that might be applicable to your particular situation. Unlikely fix, but worth a look.