[求助] modelsim仿真出现的问题,求赐教。

仿真错误提醒如下：

# ** Error: (vsim-SDF-3894) floating_led_v_fast.sdo: Compiled SDF file was not found.
# Loading work.CYCLONEII_PRIM_DFFE
# ** Fatal: SDF files require Altera primitive library
#    Time: 0 ps  Iteration: 0  Instance: /floating_led_test File: F:/floating_led/simulation/modelsim/floating_led_test.v
# FATAL ERROR while loading design
# Error loading design

求赐教。