What's the issue with one specific valid account in accessing skype?

Solution 1:

Apparently this is common. It has to do with previous chat history. Try this:

$ sqlite3 ~/.Skype/[YOURUSER}/main.db
sqlite> DELETE FROM Messages WHERE type=68;
sqlite> .quit

This will delete all old file transfer history, but messages should still remain.

Edit If you don't have sqlite3 installed, install it:

sudo apt-get install sqlite3