I got some more information from my "German connection" about Dieter Wieser who just got back in the picture along with Joe Jackson.
I have seen the original documents for MJ Net Entertainment AG, Wiesner's and MJ's first company. According to this both Wiesner and his then partner retired from the company around October, 2003. Later in 2004 the company has been dissolved, because they didn't leave up to the bankrupcy rules. Previously it has been funded from 50.000 EUR by Jurgen Bachus and Reinhard Moller.
It's been finally closed down in January, 2010.
Interesting that the new company around him, UD Group has been suspended in Switzerland previously.
Wiesner came up with something new at www.thewiesnercollection.com, that will be a collection of memorablias Wiesner collected or tried to sell over the years related to MJ.