Can't drop database??? WHY???

Hi all, we are running Informix OnLine 5.01 on SCO 3.2v4.2 and sometimes, when I am try to run this command --------------- 8< ---- cut here ---- 8< ---------- $ echo "drop database b_00014" | dbaccess - --------------- 8< ---- cut here ---- 8< ---------- I receive this in answer --------------- 8< ---- cut here ---- 8< ---------- 214: Cannot remove file for table (syscolumns). 106: ISAM error: non-exclusive access. Error in line 1Near character position 21 --------------- 8< ---- cut here ---- 8< ---------- but tbstat -ukF says --------------- 8< ---- cut here ---- 8< ---------- RSAM Version 5.01.UD2 -- On-Line -- Up 04:47:13 -- 18960 Kbytes Users address flags pid user tty wait tout locks nreads nwrites 800019f0 ------D 1633 informix tty01 0 0 0 540 2 80001a60 ------D 0 informix tty01 0 0 0 0 0 80001ad0 ------F 1634 informix 0 0 0 0 0 3 active, 20 total Transactions address flags user locks log begin isolation retrys coordinator 800022b0 A---- 800019f0 0 0 NOTRANS 0 80002650 A---- 80001a60 0 0 NOTRANS 0 2 active, 20 total Locks address wtlist owner lklist type tblsnum rowid size 0 active, 10000 total, 1024 hash buckets Fg Writes LRU Writes Idle Writes Chunk Writes 0 0 0 429 address flusher snooze state data 80001ad0 0 60 I 0 = 0 states: Exit Idle Chunk Lru --------------- 8< ---- cut here ---- 8< ---------- online.log don't report any errors and/or warnings. WHAT'S WRONG ??? HELP ??? TIA Max F. Bilyk