I'm not to sure about the technicalities involved here but a lot of people here in TX are saying that Texas courts have no jurisdiction in this matter. This is a private business in another country outside of North America. I'll post some local articles on the matter
It depends on where Kop Holdings, the parent company, is said to be headquartered.
EDIT: I've looked into it and the injunction was filed through Kop Investments which is located in Texas, but really has nothing to do with the running of the club.
It's not difficult to gain an injunction, you don't have to prove anything to have one done. It merely stops the sale from going through until the particular court can review the case. Considering Hicks has defaulted on the loan and signed away his controlling stake in the club, he won't win in Texas and he knows it. He's just stalling to attempt to send the club into administration and chase off Henry so he can do what Gilette did and sell his half of the club in an attempt to make some money.