Your having problems with your Memory or Files itself, To fix the Memory, Press the Gear at the Top Right Corner, Then it should be set to Default, 512 MB, Change that as high as it can go,
As for the File Problems, do %appdata% in the Application called "Run" Then find, .technic After that is found press Modpacks,
Find Tekkitmain
Tekkitmain = Tekkit Space (Main Tekkit)
Tekkitlite = Tekkit Lite Modpack
Tekkit = Tekkit Classic Modpack
Then After inside of that Folder (tekkitmain) Press crtl+a and then Right click and Press Delete, After done, Go back Into your Technic Launcher, Press Play On Tekkit Space (Main One) And let it download the Files.
These are the two Solves I know of, If this Continues not to work, Please Contact the Staff at Technic , Or my Personal Fav, Restart your Computer
Goodluck! And also If you need more help contact me on Skype: XeX Depleted
Thats my Username!