Vaclav Havel, was one of the leading figures of the Velvet revolution that toppled the Czech communist government.
He was arrested multiple times by the regime, the longest being for four years. The article doesn't make clear what he was charged with and one suspects that they are merely trumped up charges to get rid of a trouble-maker. It's not the first time that governments have done this.
Q. How many times was he arrested and under what charges?
I am not sure a total of arrests could be made short of writing a biography, but two particular cases can be found detailing charges.
The first case is discussed on a site here:
The regime couldn't very well prosecute Havel for agreeing with it, so they officially charged him with smuggling documents out of Czechoslovakia that were published abroad - including, of course, the Charter 77 declaration.
The second case, and resulting in the longest imprisonment, is discussed in Making History: Czech Voices of Dissent and the Revolution of 1989 edited by Michael Long. This states that the charge was
'subversion of the Republic', according to Article 98 of the criminal code
This charge resulted in Havels sentencing for four and one-half years.