Believe the message and act on it NOW! You are advised that there is a small error on one disk in a RAID0 array, and you should back up the ENTIRE RAID0 array. Do that as soon as possible. If you can't do it right now, don't use the machine until you can!
This is the big risk with RAID0. For it to work, BOTH disk units must be working almost flawlessly. If either one fails, you CANNOT recover ANY of your data. You are lucky so far. In your case the system is warning you that only a small part of one disk has failed, probably involving bad data that will ruin one or a few files. So it is still mostly working and you CAN actually recover the majority of the data on the array. What you do not know is how long your luck will hold up! A failure like this just might be a one-time deal, or it might be the beginning of many failures - you have no way of knowing. So back up while you can.
Once that is done, I strongly recommend: VERIFY that the backup files are good. On occasion people find to their huge dismay that their "Backup" is useless! So before abandoning the RAID0 array, make sure the backup has everything from it usable.
Now you can consider how to examine the two disks from the array, whether to replace one or both, whether to try fixing the problem and re-use the disks if you think they are still reliable - several choices. But you cannot do any of this until you have your data safe. Plus, you may well want to arrange at least a temporary replacement disk to keep running while you figure out the failed array problem.