这个是什么意思？哪里出错了？求助！

斯坦福的桥

**  ERROR WHILE CHECKING INPUT SPECIFICATIONS FOR VARIED VARIABLE IN       SENSITIVITY BLOCK: "N-R"       THIS VARIABLE IS NOT SPECIFIED IN THE BLOCK.       YOU CAN PROVIDE AN INITIAL ESTIMATE IN THE BLOCK       OR VARY ANOTHER VARIABLE.       VARY SENTENCE NUMBER 1

这段是哪里出错了？新手不明白，求教！