'Supernodal' problems are irritating errors. Whenever such errors appear, you must first check if the placement of contacts in your SDE file is okay. If that is okay, then you can make changes in the Math section. However, the best thing is to change the meshing specifications, which usually works.

Regarding the second error of 'Linear System', I don't have much of an idea, but you may try with changing the meshing specifications. I hope it works. Thank you.

Thank You Very Much Rupam Goswami.

My pleasure.