Before select try:
FLUSH &&- to commit changes to disk
SYS(1104) && - to clear VFP memory buffers

If it does not help, try to play with SYS(3050) - to limit VFP memory usage.
Otherwise try to achieve the result step by step using multiple select statements.

>The following SQL statement generates error 43 - There is not enough memory.
>
>SELECT ;
> CM.TA_EnrlID,;
> CM.TA_PtntID,;
> SUM(SOURCE.TA_PYMT) AS DrillItem ;
>FROM ;
> DRILLENRLTMP146897616_A CM LEFT OUTER JOIN TRANMASTERE1T1 SOURCE ;
> ON CM.TA_ENRLID = SOURCE.TA_ENRLID ;
> AND CM.TA_PTNTID = SOURCE.TA_PTNTID ;
> AND CM.TA_YEAR = SOURCE.TA_YEAR ;
> AND CM.TA_MONTH = SOURCE.TA_MONTH ;
> AND CM.TA_PCPID = SOURCE.TA_PCPID ;
> AND CM.TA_DEMOID = SOURCE.TA_DEMOID ;
> AND SOURCE.TA_YEAR=2000 ;
> AND SOURCE.TA_PCPTPID = 7 ;
> AND SOURCE.TA_PCPID = 236 ;
>GROUP BY ;
> CM.TA_EnrlID,;
> CM.TA_PtntID ;
>INTO cursor sg1 nofilt
>
>If we remove the final SOURCE.TA_PCPID = 236 line, it runs fine. Looking for any ideas here.
>
>Thanks,
>Steve