>Hi,
>
>I have trapped (using Try / Catch) an error "File is not open" in the following section of the code:
>
>

>IF SELECT("V_WO_NUM") > 0 
>	SELECT V_WO_NUM
>	INDEX ON FIELD1 TAG FIELD1
>	INDEX ON FIELD2 TAG FIELD2
>	INDEX ON FIELD3 TAG FIELD3
>	INDEX ON FIELD4 TAG FIELD4
>	INDEX ON FIELD5 TAG FIELD5
>	INDEX ON FIELD6 TAG FIELD6
>	SET ORDER TO TAG FIELD3
>ENDIF 
>

>
>Before the above code the cursor V_WO_NUM is created by SQL SELECT (getting data from a VFP table).
>
>What could possible be wrong with the above (not one time but almost every other day) that it causes the problem? And I could never duplicate this error on my PC.

The SQL SELECT that creates the V_WO_NUM cursor may be creating a filtered result set rather than an actual cursor. IF that's the case the cursor will have no presence in the file system, so any attempt to INDEX it will fail.

You can address this by adding NOFILTER to the end of the SELECT that creates the cursor. That will force the cursor to actually exist in cases where it otherwise might not.

As for it happening on one machine but not another - ironically, it will tend to happen more often on machines that have more available RAM and other resources. It may also happen more often on machines working against smaller data sets or cursors.