[求助]这段AS代码有什么问题？

久远的星光

这段AS代码有什么问题
版本是AS2.0，调试时发现M1.digit等没有被赋上相应的值，而是显示undefined
loadVariablesNum("count.txt", 0);
set("M1.digit", c.substr(1, 1));
set("M2.digit", c.substr(2, 1));
set("M3.digit", c.substr(3, 1));
set("M4.digit", c.substr(4, 1));
set("M5.digit", c.substr(5, 1));
set("M6.digit", c.substr(6, 1));
set("M7.digit", c.substr(7, 1));
gotoAndPlay("startover");