我的300程序，如果把硬件配置文件和程序文件分别单独下载，CPU正常运行，程序也能正常运行。但是如果在主页面里选择整个站编译和下载进去的话，程序也能正常运行，但是编译就会有警告，编译结果如下：

Date: 06/09/2009 time: 01:13:14 PM
Compile:
永川窑尾\SIMATIC 300\硬件
-> Object was compiled without errors


Date: 06/09/2009 time: 01:13:17 PM
Compile:
永川窑尾\SIMATIC 300\CPU 314\S7 程序(1)\块
-> Object compilation was executed (with warnings)

Warning: The S7 program contains the following blocks that are referenced but not available:
SFC58


Date: 06/09/2009 time: 01:13:23 PM
Compile:
永川窑尾\SIMATIC 300\CPU 314\连接
-> Object was compiled without errors

划横线的为警告部分。虽然对程序运行没有影响，但是我想弄清楚为什么会有这个警告，如何解决，请高手指点一下哈！