I have fixed this problem. I made it so when I use the TechnicLauncher.exe it will ask me if I want to change the default directory.
I have no definite answer, but what I did do is:
-I went to my AppDataRoaming.technic folder and deleted the setting.yml file.
-I deleted a problem associated with the TechnicLauncher.exe in my registry. (Only do this if you know what you're doing in regedit)
Hope this helps as this is a very weird bug.
Also if you encountered this bug and can not delete the massive tekkit folder directory due to the source file path being too long, you will have to download Delinvfile (google it) and use it to delete the whole directory. Use it with caution.
If you do not want to download any programs, because you are worried it will contain a virus (Delinvfile is virus free). There is another way without any downloading, but it is not 100% and it CAN take you a very very very long time. What you have to do is rename every tekkit folder to 1 (if there are subfolders in the tekkit folders you must name them to 2,3,4,5,etc). You are basically shortening the character length of the directory. If it is short enough, it will delete. If it doesn't delete then it is just too long. Try booting in safe mode, but I have no other answers other than that.