MyWI now works good on my ipad with 4.3.3. I have finally uninstalled the Free version downloaded from another sources repository and installed the MyWI OnDemand from Cydia repo.
After I uninstall again this version, and tried again with the free version from another repository. And it works perfectly.
Dont know the reason why it wasnt working before. Maybe some packages MyWi OnDemand brings than the Free version. Try to install it without any errors when you are installing the packages.
best,
Dan