writing UDF in AcuSolve

Hello expert,

I'm working on a simulation where the material is a mixture of N2, Co2 & O2.

I use species transport function to define the gas mixture.

Now, the viscosity and density of this mixture will be calculated by UDF with below equation:

Gas_vis = VisO2 * specO2 + VisCo2 * specCo2 + VisN2 * (1 - specO2 - specCo2)

where VisO2, Co2, N2 are user input values; specO2 & specCo2 are species data at each elems, provide by acusolve udf.

To be honest, i don't have much experience in this domain and having trouble defining specO2 and specCo2.
Below is my definition of specO2 & specCo2:

When compiling, acusolve notified there are errors at line 50 & 51.
Could you help me check & modify it for me?

Attached is my full udf.

Thanks in advance!