What Adder didn't mention and it is very important to understand is that in the scenario mentioned... UBCD4Win is based off of BartPE and PE environments do have some special requirements that must be met for any program to work properly on them.
One of the general requirements is to understand that if a system is booted from a Windows based PE CD, that the system area's such as %Windir%\system32 and %Windir%\system32\drivers are not normally ( I'll get back to why I underlined "normally" later ) writable. A program such as Defraggler that uses being writable as a criteria to see if a user is an admin user, will fail ( normally ).
So this is why Adder's statement about being able to be run from CD does have some merit. I still have some reservations about the statement "but obviously not with any help from this forum though" which shows a complete lack of respect for the others that do provide help on this forum. I do feel that statement was very uncalled for and I hope it won't reflect on the whole PE community because of this users lack of respect for what help is provided here. But, enough of that...
The are several possible directions that could be taken to resolve this type of issue when addressing read only media like PE builds have. Some of the possible solutions that could be done from the program itself are... to not even require that a service and file be added, if they are required that they be added to a %TEMP% file location instead, to work with an existing SSDefrag.sys file if its on read only media... and I'm sure many other possible solutions that I am not able to come up with and will therefore leave to the programmers to come up with.
I mentioned that normally there are issues with PE based CD's... There are also solutions available for BartPE builds that would allow Defraggler to be used now, just the way it is, but they do require additional requirements to be met. Specifically, to add another plugin to a users PE build called the FBWF plugin. This plugin requires the user to download the Microsoft's File Based Write Filter's files ( FBWF ) and add it's files to a simple plugin. This plugin allows a PE build to use read-only media as if it were read-write media by allocating some ram memory and then "faking" the writes virtually... It's not an elegant solution, but it works in many cases such as this one. Another issue with using this solution is that the FBWF files needed are not freely distributable by third parties, but still they are freely available from Microsoft... So it is already "do-able" but it takes some prerequisites be met to be able to have it work properly.