modelsim 6.5仿真遇到了问题,请高手指教

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用modelsim 6.5仿真为什么会报下面的错误？请高手指教

vsim work.vtf_test
# vsim work.vtf_test
# Loading work.vtf_test(fast)
# Loading work.modelsim_test(fast)
# Loading work.maxii_io(fast)
# Loading work.maxii_lcell(fast)
# Loading work.maxii_asynch_lcell(fast)
# Loading work.maxii_lcell_register(fast)
# Loading work.maxii_io(fast__1)
# ** Error: (vsim-SDF-3894) modelsim_test_v.sdo: Compiled SDF file was not found.
# ** Error: (vsim-7) Failed to open SDF file "modelsim_test_v.sdo" in read mode.
# No such file or directory. (errno = ENOENT)
# ** Error: (vsim-SDF-3445) Failed to parse SDF file "modelsim_test_v.sdo".
#    Time: 0 ps  Iteration: 0  Region: /vtf_test  File: E:/EX13/modelsim_test/simulation/modelsim/vtf_test.v
# Error loading design