Error while calculating Variance

Hi guys, i'm trying to calculate the variance using the funcion var, but i'm getting this error

"Error using size Dimension argument must be a positive integer scalar within indexing range.

Error in var (line 95)

n = size(x,dim);

Error in Untitled (line 235) var1=var(t1,trm1,Et01);"

Already tried to change so many things, but nothing. Any help will be appreciated, thank you.

[Walter Roberson]

You are passing three inputs to var. What role do you expect each of those to play?