Can anyone help me with this error?

I am testing streaming to our delivery partner and I'm intermittently getting a dshow error.
I've pasted some of the streaming log below.

My test source is an H264 video recording from a live camera. The plan is to get this working offsite in a lab before moving the streaming server on site.

frame=110458 fps= 25 q=32.0 size= 470975kB time=01:13:38.25 bitrate= 873.2kbits/s
frame=110468 fps= 25 q=32.0 size= 471013kB time=01:13:38.66 bitrate= 873.2kbits/s
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (62% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (63% of size: 256000000)! frame dropped!
frame=110477 fps= 25 q=30.0 size= 471046kB time=01:13:39.02 bitrate= 873.2kbits/s
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (63% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (62% of size: 256000000)! frame dropped!
frame=110492 fps= 25 q=32.0 size= 471101kB time=01:13:39.62 bitrate= 873.2kbits/s
frame=110509 fps= 25 q=34.0 size= 471161kB time=01:13:40.30 bitrate= 873.2kbits/s
frame=110529 fps= 25 q=32.0 size= 471255kB time=01:13:41.09 bitrate= 873.2kbits/s
frame=110544 fps= 25 q=32.0 size= 471321kB time=01:13:41.71 bitrate= 873.2kbits/s
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (63% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (65% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (67% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (69% of size: 256000000)! frame dropped!
frame=110546 fps= 25 q=32.0 size= 471375kB time=01:13:41.77 bitrate= 873.3kbits/s
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (70% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (71% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (70% of size: 256000000)! frame dropped!
frame=110555 fps= 25 q=32.0 size= 471413kB time=01:13:42.13 bitrate= 873.3kbits/s
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (71% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (70% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (70% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (72% of size: 256000000)! frame dropped!
frame=110563 fps= 25 q=34.0 size= 471444kB time=01:13:42.50 bitrate= 873.3kbits/s
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (69% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (69% of size: 256000000)! frame dropped!
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (70% of size: 256000000)! frame dropped!
frame=110576 fps= 25 q=32.0 size= 471493kB time=01:13:43.14 bitrate= 873.2kbits/s
[dshow @ 0075CBE0] real-time buffer[vMix Video] too full (70% of size: 256000000)! frame dropped!


Any help / thoughts appreciated.

thanks
andy