This is Judy from LightHeart Gear (under my husbands log in) - Yes, the tent is repairable, the tie out webbing probably needs to be removed first, and patches glued over the ripped area, the webbing needs to be re-sewn with some sort of support -
use regular contact cement, tape off the areas you plan to patch, smear some contact cement on the area and on the patch, wait for them to dry, stick together and roll over it with a wallpaper roller - use pressure. then put the webbing back, put a piece of grosgrain ribbon or something similar on the back side of the tent and sew back in place. Then put some cuben tape over the needle holes. - someone mentioned 'clamping it' - I have no idea what this is, just get a good roller and roll over it after putting the 2 parts together. I have a wide rubber roller (from scrap booking section of craft stores) and a hard plastic wallpaper roller that I use. If I can glue a seam - that's all I do, if it has to be sewn, and most of my tents do have to be sewn, then they get sewn. Areas that are under very high stress get heavier cordura nylon patches to support the seams.
I sew cuben all the time (wish I didn't) but any seam that gets any stress will have to be taped, especially if it's cuben to cuben. generally if I sew cuben to mesh or zippers it doesn't always get reinforced, but sometimes it does. This is why I hate working iwth cuben, it is VERY labor intensive. Sew a seam, tape it, cut a pice, glue a patch on it before sewing... it takes twice as long to make a cuben tent as it does to make a silnylon one. I know I've been threatening for a long time to quit working with cuben, but somehow, my stock just keeps getting replenished, and I keep getting orders. Some day...
Along the ridge line, I would probably just tape it to reinforce the area, it may need a patch glued on , but probably not. One of the reasons it's pulling apart is that it's not a lapped seam - this was a plain seam sewn on a single needle machine and then folded over - so the one side wehre it is pulling apart does not have the reinforcement that the other side of the seam has. Occasionally this type of seam is needed, but a true lapped seam is much stronger. - it requires a sewing machine that has 2 needles, 2 bobbins and special folders.
I'm curious, if this is the outside of the tent, how is it seam seled? This is why I have never been an advocate of using silnet as some have on cuben, the holes do stretch, and silnet does not bond with cuben. I tape all outside seams to seam seal and reinforce.
Also, since this is brand new - return it!