If someone is no stranger to allegations of copyright infringement, it means he gets accused of copyright infringement a lot.
No, downloading music via a program such as LimeWire is not legal. It is not legal to obtain music unless you have paid for it due to copyright infringement.
Crediting a source will not exempt you from being charged with copyright infringement.
No, It is illegal. It is a Copyright Infringement and is very serious. It's the same as stealing.
It is not legal. If you do not own rights to the music it is copyright infringement.
By law, libraries are specifically exempted from copyright infringement. (see related links for the specific language of the law)
The best way to prevent infringement is to get permission for using any content that you do not own. You can also create your own original content and become a copyright owner yourself!
"Copyright in fragment" is a common misspelling of "copyright infringement," which is the violation of copyright.
Copyright infringement is primarily a civil offense however there are options to prosecute criminally in the case of "willful and deliberate" acts of infringement. Ignorance of the existence of copyright is not a viable defense to infringement. If an author is convicted of copyright infringement the publisher can be held liable for contributory infringement if it can be shown that they had knowledge of the infringement prior to publication. If, by a preponderance of the evidence, infringement can be shown then yes a damages award to the copyright holder can be granted.
The legal term (and concept) is "copyright infringement". This is more accurate, as "violation" is more properly a term for criminal activities, not civil actions, and copyright law is Civil Law (though, unfortunately, there now also exists certain Criminal Laws for certain copyright infringement situations). Specifically, copyright infringement is the copying (in whole or in part) of a copyrighted work without the express consent of the copyright owner of that work. There are specific exceptions to where certain amounts of copying are legal (most prominently, but not exclusively, the "Fair Use" doctrine).