Launcher can't install mod pack

[Ron_Swansons_Mustache]

I was playing the Ultra Modded Survival mod pack and it was lagging and not loading things so I went to re-log and the mod pack wouldn't load so I went to re-install it and the pack wouldn't install and an error message came up saying:

 

Error installing the following pack: Ultra Modded-Survival

 

An error occurred while attempting to delete 'C:UsersJeremyAppDataRoaming.technicmodpacksultra-modded-survival-packmods1.6.4CodeChickenLib-universal-1.6.4-1.0.0.6.2.jar' from the cache'

 

Please check your system settings.

 

It was working perfectly a few minutes ago and now I can't play it.