Fixed the bug (was because currdist was sparse when using Tan improvement, and cannot use sparse matrix as input to fprintf).
And you can now set the tolerance using:
heteroagentoptions.toleranceGEprices=10^(-4); % Accuracy of general eqm prices
heteroagentoptions.toleranceGEcondns=10^(-4); % Accuracy of general eqm eqns
[These show the default values.] By default, the stationary general equilbirium is computed using matlab fminsearch(), and these control what fminsearch() options call TolX and TolFun, respectively.