Not paying mana costs and stuck at precombat

[Robs]

I got Xmage a few days ago and decided to finally try it out today. The problem is my game is glitching so much I cant play, let me explain. So i'll start a match with the AI and go first. Ill play a land and then try and play a one mana card. The card ether vanishes then shows up in my hand 10 seconds later or goes onto the stack and says to pay the mana cost but it wont let me play it even after i've tapped the right land. Also whenever I tap a land it goes halfway through tapping then untaps. Last thing whenever the AI reaches precombat it gets stuck there forever. If i could have some help that'd be great i'm pretty sure I have the latest version as I hit update to see if I had an old version and it updated fine, maybe I have an older version of java?