关于optistruct求解报错的问题！！！

用optistruct计算时老是出现同样的错误，已设置subcase指定力和约束，还是报同样的错误。跪求大侠解决啊！
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** **
** **
** OptiStruct 11.0 **
** **
** Design and Optimization Software **
** from Altair Engineering, Inc. **
** **
** **
** Windows XP Professional SP3 (Build 2600) 11JSZX039 **
** 4 CPU: Intel(R) Core(TM)2 Quad CPU Q9500 @ 2.83GHz **
** CPU speed 2850 MHz **
** 2144 MB RAM, 4095 MB swap **
** **
** Build tag: 0556688_5333110_Ci32RH11M:58501-000 4000 **
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** COPYRIGHT (C) 1996-2011 Altair Engineering, Inc. **
** All Rights Reserved. Copyright notice does not imply publication. **
** Contains trade secrets of Altair Engineering, Inc. **
** Decompilation or disassembly of this software strictly prohibited. **
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*** ERROR # 1260 *** in the input data:
Missing SUBCASE information in the input file.
Detected while reading line 1 from file G:/lianxi/3.fem:
*** ERROR # 61 ***
No grids found in the input data.
*** ERROR # 61 ***
No elements found in the input data.
*** ERROR # 61 ***
No properties found in the input data.
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RESOURCE USAGE INFORMATION
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MAXIMUM MEMORY USED 32 MB
MAXIMUM DISK SPACE USED 0 MB
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COMPUTE TIME INFORMATION
------------------------
EXECUTION STARTED Tue May 13 08:44:44 2014
EXECUTION COMPLETED Tue May 13 08:44:44 2014
ELAPSED TIME 00:00:00
CPU TIME 00:00:00
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*** PROGRAM STOPPED: FATAL ERROR(s) ENCOUNTERED.
***** END OF REPORT *****
For Useful OptiStruct Tips and Tricks, go to the URL:
http://www.altairhyperworks.com/tips.aspx
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There were 4 error messages during input processing.
The first message is repeated below:

*** ERROR # 1260 *** in the input data:
Missing SUBCASE information in the input file.
Detected while reading line 1 from file G:/lianxi/3.fem:

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