I've seen people manage very well with that kind of schedule, it depends on what condition you are in and how intensely you work out though. If you damage your muscles a lot on one day, work them again the next say through running, then the following day do the same workout that damaged them in the first place you will burn out quickly. If, however your body is conditioned and used to that type of volume then you shouldn't have a problem. Usually when I set up a very heavy schedule for myself, weight training plus many cardio sessions I burn out quickly, get sick and have to come back to reality and do a little less. Give it a try and assess how you feel: if you are constantly exhausted, find yourself dragging yourself through the workouts rather than enjoying them and generally feeling like crap cut 2 days of activity out, OR make two of your exercise days very light ie: use the rollerblading the same way one would a walk, rather than an intense cardio. Plus, you don't need to do abs every night. They're muscles too and have to recover some time! Always follow something heavy with rest, or something very light like walking, easy biking or rollerblading.

Take care,
Meg