Internal Error: Sub-system: VRFX, File: /quartus/synth/vrfx/vrfx_verific_elaborator.c

sir i've installed 30 day trial version of quartus 12.1sp1 recently and
while compiling my design (using stratix), i am facing an internal error :
Internal Error: Sub-system: VRFX, File: /quartus/synth/vrfx/vrfx_verific_elaborator.cpp, Line: 2083
c
Stack Trace:
0x5c356: VRFX_VERIFIC_VHDL_ELABORATOR::create_port_hdb_type + 0x266 (synth_vrfx)
0x5c419: VRFX_VERIFIC_VHDL_ELABORATOR::create_port_hdb_type + 0x329 (synth_vrfx)
0x5bb38: VRFX_VERIFIC_VHDL_ELABORATOR::register_ports_type + 0x1b8 (synth_vrfx)
0x5aedc: VRFX_VERIFIC_VHDL_ELABORATOR::elaborate + 0x1ec (synth_vrfx)
0x556a6: VRFX_ELABORATOR::elaborate + 0xb6 (synth_vrfx)
0xa4fd1: SGN_FN_LIB::elaborate + 0x131 (synth_sgn)
0xa776a: SGN_FN_LIB::start_vrf_flow + 0xa (synth_sgn)
0xa894a: SGN_FN_LIB::start + 0x57a (synth_sgn)
0x7d08a: SGN_EXTRACTOR::single_module_extraction + 0x15a (synth_sgn)
0x89c13: SGN_EXTRACTOR::recursive_extraction + 0x193 (synth_sgn)
0x8d12a: SGN_EXTRACTOR::extract + 0x1aa (synth_sgn)
0x12840: sgn_qic_full + 0x140 (synth_sgn)
0x4488: qsyn_execute_sgn + 0x118 (quartus_map)
0x19022: QSYN_FRAMEWORK::execute_core + 0x102 (quartus_map)
0x1c6ec: QSYN_FRAMEWORK::execute + 0x2bc (quartus_map)
0xfbb1: qexe_get_tcl_sub_option + 0x1641 (comp_qexe)
0x1203b: qexe_process_cmdline_arguments + 0x3cb (comp_qexe)
0x12123: qexe_standard_main + 0x83 (comp_qexe)
0x17d9e: qsyn_main + 0x5e (quartus_map)
0x4d41: msg_main_thread + 0x11 (CCL_MSG)
0x1be8: _thr_final_wrapper + 0x8 (ccl_thr)
0x5425: msg_thread_wrapper + 0x85 (CCL_MSG)
0x37f7: mem_thread_wrapper + 0x47 (ccl_mem)
0x6051: msg_exe_main + 0x81 (CCL_MSG)
0x188bc: _main + 0x1c (quartus_map)
0x22904: __ftol2 + 0x1ce (quartus_map)
0x1776e: RegisterWaitForInputIdle + 0x48 (kernel32)
End-trace
Quartus II 32-bit Version 12.1 Build 243 01/31/2013 SJ Full Version
Service Pack Installed: 1

plz help me on this