Here's how I would go about debugging this issue (after testing it out in a different browser first -- occasionally this works):
Try isolating the problem. You can achieve this by removing lots of code, seeing if it works, then adding some code back, seeing if it works, etc. -- once it stops working, you know that the problem is in that last chunk of code you added back. For example, start by completely removing all of the block code except for the class/function definitions -- so you just have an empty shell that does nothing. If it won't install, then you know there is a problem with the basic setup of your block (perhaps something wrong with file names or class names or function names? Or perhaps file permissions on the server?). If it does install, then you know the problem is with some of the actual code you wrote, so start adding code back bit by bit and keep uninstalling/reinstalling until it doesn't work anymore.

Best of luck!