Help needed badly: Trouble with in-game communication

[Shnikshnak]

Greetings fellow players,

I suffer serious problems with my empire communication and did'nt found a clue anywhere. Maybe one of you can help out?

I try to "send message" from the empire screen, getting no "message sent" flag, when I finished a message with "send message".
If I try to send a message again then, the communication dialogue will not pop up again (like it is, when a message was sent.
Messages sent this way (with no message sent flag), were not received by the other players.

So I am not able to trade or to propose or accept treaties, too. I am in war with another race for example and can not change this status, because I am not able to accept a T&R treaty.

What I did:
* I reinstalled SE4. No changes.
* I tried it in another game (with the same SE4 repository): I got the "message sent" flag ... but it seems that these message end in a data nirvana as well.

Any ideas? Anyone got the same problems?
First time I mentioned this was when I came back from holidays and my AI messed up my empire, but this was 2 or 3 turns ago.
HELP!

Greetings
Shnikshnak