Kudos to Richard Simms and his TSM info website:
http://people.bu.edu/rbs/ADSM.QuickFacts

I began experienceing  a series of these:

07/09/2003 9:04:14 AM ANR0102E asalloc.c(4699): Error 1 inserting row
in table "AS.Segments".
07/09/2003 9:04:14 AM ANR1092W Space reclamation terminated for volume
000470 - internal server error detected.
07/09/2003 9:08:49 AM ANR0102E asalloc.c(4699): Error 1 inserting row
in table "AS.Segments".
07/09/2003 9:08:49 AM ANR1092W Space reclamation terminated for volume
000408 - internal server error detected.
07/09/2003 9:11:52 AM ANR0102E asalloc.c(4699): Error 1 inserting row
in table "AS.Segments".
07/09/2003 9:11:52 AM ANR1092W Space reclamation terminated for volume
000417 - internal server error detected.

I did a dsmserv dbaudit fix=no deatails=yes

70 some millions records later it issued a series of messages
indicating problems.
I brought the TSM server back online and followed the recommendations
on R. Simms site and did a query volhist type=STGREUSE

Found one, set it readonly, did a move data, and subsequent
reclamations went to completion.

A very  obscure senario.