os_msys_get_pkthdr always return null

[then yon]

Dear Support,

I having issue with mqueue that the following code always return me 
error after i update myNewt to developer version.

struct os_mbuf *om = os_msys_get_pkthdr(0, sizeof(some_struct));

if(om == NULL)
{
    console_printf("Spi err 02\n");
    return -2;
}

By disabling nffs filesystem coding, it worked perfectly.

Do anyone have any idea on this? Appreciate on your help.

Thank you.

Regards,
Then Yoong Ze