Redirect after empty register form

I am trying to make a separate registration form for 2 types of users on my website: e.g. apples and oranges.

Therefore, I use the following GET requests:

• http://ift.tt/1KkBtiP


• http://ift.tt/1B7rndE

These URLs are called when a user pushes on the respective button for registering oranges or apples and a specific registration form appears. My code also checks whether their are no empty fields. And if there are, it gives an error to the $errors variable.

Till now, everything works fine. BUT: when an error occurs (as e.g. an empty field), it plots the error information on http://ift.tt/1KkBumY. This means: the role specific fields are missing here!

Can someone help me how to plot the errors on the correct page (e.g. http://ift.tt/1KkBtiP) without erasing the completed fields?

Thanks in advance!