P90X and Mud Sweat and Tears Training

I am currently finishing the second month of P90X and have one month to go and am also now considering doing a 10k obstacle race with friends May 4th. Its called Mud Sweat and Tears and we are doing the race as a team. I haven't run for quite some time due to a muscle issue that only flares up when i have run. I took the summer off from running and haven't run since but have done Chalean extreme all the way thru and some extra and I have been able to do all of P90X without modifying anything but am nervous about running and feeling the injury again and it affecting being able to do P90x to the finish as well as being able to do this race...

Any thoughts or ideas? I went to physio and chiropractor and was told needed time for the muscles to heal and not to do anything that caused it pain so have done just that. I had been traingin for a half marathon and on my longest run of 19.6km i felt the muscle pain that has since haunted me when running. So i could run back then. Now i havent run since summer this last year, and wonder how long it will take me to train at 3 times a week running with only about 5 weeks to train once i finish p90x...

Obviously, if I feel a niggling of pain i will be stopping the run and walking my way home so as to not cause worse injury, but will only having April to train to run again before the race be enough? i plan on using parts of p90x as the cross training and strength training on non running days for that month too...

I will be doing another round of p90x as soon as the race is over as well...