reorg rebuild failed

I try to rebuild all index on a table say mytab like(my db is ASE 12.5):

reorg rebuild mytab

looks like most of indexes rebuild but at the end of the processing, then got following message:

90 REORG REBUILD of 'mytab' terminated due to error or user interrupt.

91 Number (1105) Severity (17) State (1) Server (MYSERVER) Can't allocate space for object 'mytab' in database 'mydb' because 'myseg' segment is full/has no free extents. If you ran out of space in syslogs, dump the transaction log. Otherwise, use ALTER DATABASE to increase the size of the segment.

then I check segment space with following sql:

select segment = s.name,

       free_pgs = sum(     

       case u.segmap

         when 4 then lct_admin("logsegment_freepages", db_id('mydb'))  - lct_admin("reserved_for_rollbacks", db_id('mydb'))

         else curunreservedpgs(u.dbid, u.lstart, u.unreservedpgs)

       end),

       free_M = sum(     

       case u.segmap

         when 4 then lct_admin("logsegment_freepages", db_id('mydb'))  - lct_admin("reserved_for_rollbacks", db_id('mydb'))

         else curunreservedpgs(u.dbid, u.lstart, u.unreservedpgs)

       end)*2/1024

from master..sysdevices d ,master..sysusages u ,mydb..syssegments s

where u.dbid = db_id('mydb')

and u.vstart between d.low and d.high and d.status & 2 = 2

and u.segmap & power(2,s.segment) != 0

group by s.name

and got following result (or sp_helpsegment):

all segment have free space!   data and pk of mytab is on myseg, all other indexes is on segment indexes.

3  devices has been assigned for myset. The free space of devices for myseg as below::

Not sure why. how to figure it out and resolve it?