The error should not appear, your code looks to work exept for the part of 'data' , should this instead be value?
test='eye';
value=[1,2,3];
eval([sprintf(test) '=value+1'])
eye =
2 3 4
The index exceeds matrix dimension could be related to that you have at some point declared a variable in your workspace ( or funciton or whatever ) with the name of eval.
try typing
which eval
it should return that eval is a built-in function, if it returns eval is a variable there is the reason for your error. If so just use
clear eval
