Hi @Abdollahi,
The warning can sometimes appear, typically when your data does not contain enough information for LARS to select the regressors properly. Can you find out when the warning appears, is it already in the first iteration of AKMCS? It seems you are specifying 20 initial points and 20 additional points for AKMCS in more than 10 dimensions, so only 40 points in total, that might be too little to get a reasonable answer!
The change in uq_lar.m that you mention also had to do with data/design matrix problems, but doesn’t have to do with this warning, so it won’t change anything in your case.
Regarding your second question,
I am not sure what you mean with that (how did you notice it was not used?) But can it be that LARS should be a field of APCKMCSOPTS.AKMCS.PCK instead of being a field of APCKMCSOpts?
By the way, the line Sorry, I was wrong about that, see Reliability Analysis manual, p. 40.APCKMCSOpts.Simulation.MaxSampleSize = 1e6; is only valid for MC-based reliability and will probably be ignored.
Let us know whether this helped solve your problems. Good luck! 