[Mono-list] System.IO.FileNotFoundException:System.Threading.Tasks.Dataflow

[Edward Ned Harvey (mono)]

> From: mono-list-bounces at lists.ximian.com [mailto:mono-list-
> bounces at lists.ximian.com] On Behalf Of MrBlaTi
> 
> A quick search and
> https://www.archlinux.org/packages/extra/i686/mono/files/
> tells me its part of the standart mono package, wich is, in fact, installed.
> Anyone had a similar issue, or am I just being plain dumb here?

First, even though the package is installed, make sure the file in question is actually present, without any obvious wrong permissions:
ls -l /usr/lib/mono/4.5/System.Threading.Tasks.Dataflow.dll

On my centos6 system, the path is slightly different (no /usr) but here is what I see, for comparison:
ls -l /lib/mono/4.5/System.Threading.Tasks.Dataflow.dll /lib/mono/gac/System.Threading.Tasks.Dataflow/4.0.0.0__b77a5c561934e089/System.Threading.Tasks.Dataflow.dll
lrwxrwxrwx. 1 root root   100 Apr 25  2014 /lib/mono/4.5/System.Threading.Tasks.Dataflow.dll -> ../gac/System.Threading.Tasks.Dataflow/4.0.0.0__b77a5c561934e089/System.Threading.Tasks.Dataflow.dll
-rwxrwxr-x. 1 root root 84480 Apr 25  2014 /lib/mono/gac/System.Threading.Tasks.Dataflow/4.0.0.0__b77a5c561934e089/System.Threading.Tasks.Dataflow.dll

Second, even though that seems to be the right file, there are many cases where namespaces and assembly names don't match, or multiple assemblies have the same name, etc. So just to be on the safe side, yum install mono-complete (or apt-get install mono-complete, or whatever).