The message indicates that all memory for sending high priority messages is used up. The source of the problem could be unicasts, broadcasts or multicasts that are generated at a rate the switch cannot handle. The error is related to a cosmetic bug, found at Cisco bug ID CSCeh06692.
This bug is a cosmetic one, and it does not affect the system performance. When all connected devices come up at the same time, the system uses all the vbufs. The vbufs are released later and the system functions normally. However, you can eliminate the error with an upgrade to a later code.
%SYS-3-P2_ERROR: 1/Have run out of vbufs (internal buffers)