Solve with symbols



Hello again,

I found another point, I did not find anythng about at google.

I have a bigger script but for debugging I wrote it in some lines:

(%i33) y : y(t);
(%o33) y(t)

(%i34) [eq1: x+y = 3, eq2: 2*x+y = 5];
(%o34) [x+y(t)=3,2*x+y(t)=5]

(%i40) solve([eq1, eq2], [x,y]);
apply: found y evaluates to y(t) where a function was expected.
 -- an error. To debug this try: debugmode(true);

(%i41) [eq3: x+z(t) = 3, eq4: 2*x+z(t) = 5];
(%o41) [x+z(t)=3,2*x+z(t)=5]

(%i42) solve([eq3,eq4], [x,z(t)]);
(%o42) [[x=2,z(t)=1]]

Why does %i40 throw an error? I have serveral Symbols in my script just the 
way as in %i33 and it will not be much funny to change all of them. I don't 
understand why I works with an explicit (t) at z and not with the implicit one 
with y.

Any ideas (and hopefully solutions)?
Thx
Christian