Solve Non Linear System Maple

Hi Guys :)

I need some Help with solving a nonlinear system. 

I have 3 equations.

These 3 equations have 7 unknown variables in it. But 5 of them are constants which I don't want to solve. I just want to solve three of them.

I tried it with fsolve but I always get the error :

fsolve({eq1, eq3, eq5}, {a, b, c});
%;
Error, (in fsolve) {eq1, eq3, eq5} are in the equation, and are not solved for

i tried to define the variables as Parameters but then i get this error: 

Parameters(t1, t2, t3, t4, t5, t6, t7, b1, t, v1, v2, s1, s2, j, a, b, c);

fsolve({eq1, eq3, eq5}, {ca, cb, cc});
%;
Error, (in fsolve) {b1, eq3, eq5, j, t, t1, t2, t3, t4, t5, t6, t7} are in the equation, and are not solved for

Here is the script : Non-Linear_system.mw

 has sb an Idea?