1. What's the max block_id being used by a segment (on that datafile)? If that's lesser than 31, resize the datafile.
If "select * from dba_extents where file_id = 14
and 29 between block_id and block_id+blocks -1"
returns nothing, you might be able to shrink the datafile and get rid of the corruption (if you're really lucky). Resize the datafile to the smallest possible value, then run ur dbverify.

2. If the corruption still exists, too bad. Fractured blocks cannot be fixed using dbms_repair. All you can do is sort of work around it. "Set maxcorrupt on file ## to 5;" within RMAN and RMAN will ignore the corrupt blocks during backup. All you can do is create a new tablespace, export stuff, then drop the old one.