Pspice 9.2 floating nodes error

Hello, I made an electrical design of a schematic for a project and when I tried to simulate it in Pspice to see the signals i ran into these 2 errors: ERROR -- Node N07324 is floating ERROR -- Node N06543 is floating Now, the node numbers aren't important, and I was designing a Differential Amplifier with MOS transistors, the models used are IRF150, IRF151, IRF9131 and IRF9130. The errors occur when I connect the grid of a MOS transistor to a current mirror, formed with 2 MOS transistors with their grids connected, so basically the 3 grids are connected. In Pspice, the node that links the grid of the transistor with the connected grids of the current mirror gives me one of those 2 errors ( obviously I have 2 situations in my design!! ). Could someone please help me and give me a solution to those errors. Thanks a lot!! Goodbye.