Please post your entire client side console log on pastebin.com and link your paste URL here. This is the other window that is opened by the FTB launcher. Please post any and all other logs you can provide to pastebin.com and link those as well. Logs are much easier to read when uploaded to pastebin. To prevent future issues, such as pastebin flagging your log as spam and deleting it, it is simplest to create an account on pastebin.com and use that account to upload your logs.