Well, at least some of the questions have actually been asked. Others are more in the category "Things Some People Might Want to Know", while some belong to the category "Questions I Wish People Would Ask More Often".
Glaurung is the name of a dragon from the books of J.R.R. Tolkien. You will not meet this dragon in The Lord of the Rings, but in the less frequently read Silmarillion, and in the recently released The Children of Húrin. Scatha, Glaurung's hexagonal chess playing twin brother, is named after another Tolkien dragon, which can be found in the appendices of The Lord of the Rings.
Being commercial or not has little to do with strength, and more with stability and level of support for customers. If Glaurung were a commercial program, I would feel responsibility to help customers solve problems, and to fix all reported bugs as soon as possible. I would no longer be able to take long breaks from computer chess when I am tired of it.
Another important factor is that trying to sell my engine would probably force me to close my source code in order to keep a competitive advantage towards other chess programmers. Because I think sharing and cooperation in computer chess leads to more rapid progress than secrecy and competition, closing my source code is a very unattractive option to me.
In short, the Glaurung chess engine is free because I value freedom higher than money, and because I favor cooperation over competition.
The Glaurung chess engine will remain free, for reasons explained in the answer to question 3 above. But this does not necessarily imply that Glaurung will never be commercially available in some form. It would be possible, for instance, for some big software company to use the Glaurung chess engine as the "brain" in some mass-market chess program. This could be done even without my explicit permission: Glaurung is released under the GNU General Public License, which means that users are free to do whatever they want to the program and its source code, as long as any modifications they do to the source code is made freely available to the public.
If the conditions are right, I might also be willing to do paid work on Glaurung for some software company. I would be happy to be paid to improve my engine and adopt it to the requirements of some commercial chess package. However, I would never accept such an offer unless I would be allowed to keep releasing the chess engine itself and its source code for free.
Not really. In my opinion, most computer chess enthusiasts vastly overestimate the problem of cloning. Cloning of strong open source chess programs doesn't happen very frequently, and when it does, the clones are usually detected very quickly. The occasional clones can sometimes be slightly annoying, but I think it is a very small price to pay for the numerous advantages of having strong open source chess programs.
It could also be argued that the cause of cloning is not the existence of open source chess programs, but the very fact that releasing a chess program without source code is considered acceptable. If all chess programs were released with full source code, cloning a chess engine and getting away with it would be impossible.
Just convince Apple to open the iPhone for 3rd-party developers, and you will soon be able to run Glaurung on your iPhone.
The answer is simple: Very few serious bugs. Most chess programs suffer from a vast number of unknown bugs, and could improve by hundreds of rating points by fixing them. The key to writing a strong chess program is to program very defensively and test every new chunk of code (even code which is "obviously" correct) very carefully, and to keep everything as simple and banal as possible.
Attempting to do something very complex in a low-level language like C or C++ is asking for trouble, unless you are a programming wizard. Never attempt to attack a difficult problem before you have broken it down to to tiny and trivial sub-problems, each of which can be solved, implemented and tested in isolation.
Glaurung 2 is still a work in progress. The missing features from Glaurung 1.2.1 will be added gradually. Stay tuned, and wait for the final Glaurung 2.0.
Check that the value of the "Number of threads" UCI parameter (or the "Threads" parameter in Glaurung 2) matches the number of CPU cores on your computer. Glaurung is not able to programmatically detect the number of CPUs, and may sometimes use two search threads by default on single-CPU computers. This will cause the program to run extremely slowly.
If you compile Glaurung yourself, you must also make sure that NDEBUG is defined. Otherwise you will get a Glaurung executable which runs in debug mode, and spends lots of CPU cycles constantly checking the internal consistency of its data structures.
Please make sure the file named kpk.bin is present in Glaurung's working directory. The program will not work without this file.
With Glaurung 1.2.1, it is not possible. Glaurung 2, however, uses the PolyGlot book format, and can use any PolyGlot opening book (as long as it is named book.bin and placed in Glaurung's working directory).
The Nalimov endgame tablebase code uses a license which is not compatible with the GNU General Public License, which is used by Glaurung. Implementing support for Nalimov tablebases would be technically easy, but legally impossible.