Video freezes in application with multiple libvlc instances

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I'm trying to develop an application for watching multiple RTP streams at once. However I met a very strange error. When I start sending multiple streams from server to client and on the client I accept them with VLC players (all at the same time), the video gets choppy, but never freezes completely. But when I try to run them in my own application (developed in C#, MS VS 2010), the video stops after some minutes. I wrote my own wrapper for LibVLC 1.1.7 dll. The application works perferctly fine with a few VLC instances, but once things get choppy, the videos freeze after (a random amount) some time. The instances give "ES_OUT_SET_GROUP_PCR is called too late" and image skipped messages, but that should be ok, cause the same happens when I accept the streams in normal VLC player, yet they never freeze.
Is there some option for VLC which would make it not freezing? I tried using

"--clock-synchro=0",
"--clock-jitter=0",
"--rtp-caching=1000",
"--network-caching=1000"

all of them without any observable impact.