Don't know if this is a known bug, but I haven't found it in MSDN so I'll post it here, as it can cause some funny behaviour...
Have tested this with same behaviour in VFP 6.0 and FPW 2.6.

When trying to get the rownumber of an element > 32767 it seems to 'max out', returning 32767 divided by the number of columns. It also seems always to return 1 as columnnumber for same.
As a curiosity, instead of giving an 'Subscript out of bounds', it returns the same value for element number 99999999...
Somebody's been using a signed int somewhere? :-)

DIMENSION aTmp[60000, 1]
?ASUBSCRIPT(aTmp, 59000, 1)
DIMENSION aTmp[30000, 2]
?ASUBSCRIPT(aTmp, 59000, 1)
DIMENSION aTmp[20000, 3]
?ASUBSCRIPT(aTmp, 59000, 1)

Arne