If the devices were used by Veritas before, then removed and represented without updating/removing the disks cleanly from Veritas first, then this would explain why the entries are showing in error state, as the configuration hasn't been updated cleanly.
At this point, the best bet is to:
1. remove the devices in VxVM:
# vxdisk rm <disk> ### ie: the disks shown in error
2. Remove the entries for those disks under /dev/vx/dmp and /dev/vx/rdmp
3. Rebuild the dmp device tree
# vxdctl initdmp
4. Now rescan
# vxdisk scandisks
NOTE: this still may not work as the devices were not removed cleanly, so the incorrect config may be stuck in the kernel. If the above does not work, I'd suggest scheduling a reboot rather than trying to remove the disk.info file, as this probably won't work either/may confuse the issue further.
To avoid this situation in future, ensure disks are removed from VxVM cleanly (ie: vxdisk rm, removing devices under /dev/vx/*dmp/, ensuring disks are not rescanned in after this point by stopping vxesd) PRIOR to cleaning up PowerPath and removing the disks from the OS.