Issue with code?

[wat99]

I have uploaded EPMA pyroxene data, and get this code when I run it. Any advice?

Error in pyroxene_fe3 (line 8)
I(1,1)=find(strcmp(headers,'SiO2'));
^^^^^^
Error in MinPlot (line 104)
StrctFrm=pyroxene_fe3(data,headers,wantstrctfrm); %calls pyroxene (w/Fe3+) calculation function, outputs the structural formula with cation assignment
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^