Any replace with a for scope will be treated as if it were a replace all which attempts a file lock as it doesn't know how many records it will update - the best solution I can find is that you use a scan for to go throught the table and replace record by record. e.g.

SELECT Q_IN
SCAN FOR RIGHT(UPPER(ALLTRIM(Q_IN.SEQ_CNTRL)), 2)=="WB"
REPLACE Q_IN.qintime WITH PADL(ALLTRIM(Q_IN.qintime), 8, '0')
ENDSCAN