(The requested operation cannot be performed on a file with a user-mapped section open)
Minecraft is unable to access one of its files and that is causing this crash. The antivirus program is usually the culprit. Add the FTB folder.
Zeeb in you case it is 'C:\Users\Zeebo\Desktop\FTB', to the exceptions list of your antivirus program. Be sure to check any boxes that say 'include sub-folders'.
Akeldama280 for you it would be 'C:\Users\Geff\Downloads\' which I would not suggest adding as that would mean that no file in your Downloads folder would not be scanned. Please create a folder for FTB itself like Operation_115 has and put the mod pack folders into it. Then change the 'Install folder...' inside the launcher to match the new FTB folder where ever you put it.
I can help goto the launcher settings and run the launcher with at least
3gb of ram and that may solve some problems you could also try and close some programs hope this helped
JVM Flags: 3 total; -Xms256M
-Xmx4096M -XX
ermSize=256m
JVM Flags: 3 total; -Xms256M
-Xmx3072M -XX
ermSize=256m
I appreciate the attempt to help, but please try reading the log first to find out the cause of the problem. Then suggest a possible fix based off that. Both users already have it set to 3+GB and that is not the cause of his problems.