Question: Problem with convert to - 2-D math input

Hi

I have an old maple document written as 1-D math input. In order to make the document more clear I used the convert to 2-D math input funtion.

The following expression containing a unknown function phi[0] and a guess on this function has both been converted to 2-D math input.

U0:=1/2/mu*exp(-I*theta)*(kappa*phi[0](z)-z*conjugate(diff(phi[0](z),z))-conjugate(psi[0](z)));

phi[1](z) := A[1]*z^(lambda+I*epsilon)+B[1]*z^(lambda-I*epsilon);

The first expression is converted and can be run without errors but the second expression can't. It gives the following message: "parts of the expression are unambigous. Please select on of the suggested meanings"

Why does the equation work in 1-D math and not in 2-D math?

Thanks in advance