H264 Decoder Problem

Hellow, I have trouble with H264 Decoder.

I decoded H.264 HD(1920x1080) and SD(720x480) mutually.

For changin decoding parameter(resolution etc) dynamically, I used UMC::H264VideoDecoder.Init .

But keep to change  in 3 minute, access violation happen in UMC::H264VideoDecoder !!

Access violation happen in RefreshCABACBits (umc_h264_bitstream_inlines.h line 313.

I think access violation cause by the function's paramter two (m_pMagicBits) is NULL.

How can I fix that's ?

I used Inte IPP 8.0 and w_ipp_samples_p_7.1.1.013

And execution enviroment is

OS: Windows 7 SP1,

CPU:Core i7-3770 @ 3.40GHz

RAM:4.00 GB

I attached call stack.

Please advise to me.

Thank you.