>Cetin,
>Thanks for immediate reaction. I have heard about this limitation (strange for 32bit system) and definitely some arrays will exceed 65000 elements. But what is astonishing me that before I spotted the problem I have been using also arrays which were biger than this limit. Additionally I can't find config.fwp in my system which should help in this situation a bit by proper setup. In fact I don't know how to use insert and use this file.
>Jacek

Jacek,
AFAIK you can't use an array with more than 65000 elements and no proper setup in config.fpw could cure it with current versions of VFP. OTOH you could have 65000 arrays with 65000 elements in each (didn't try - from system capacities).
Now back to your problem. There are several ways to accomplish task with respect to your original code :
***
close tables
use
use t8tresults1
select t8tresults_can.date;
from t8tresults_can;
into array a8t
append from array a8t
***

1) If field names are same directly append from t8tresults_can
append from t8tresults_can fields date
2) Instead of array use cursor

select t8tresults_can.date as FieldNameInt8Results1 ;
  from t8tresults_can; 
  into cursor crsTemp
select t8tresults1
append from dbf('crsTemp')

3) Scan t8results_can and insert into t8tresults

select t8tresults_can
scan
  insert into t8tresults1 (TargetFieldName) values (t8tresults_can.date)
endscan

4) copy to file and append from there

select t8tresults_can
copy to TempFile.txt fields date type SDF
select t8tResults1
append from TempFile.txt fields FieldNAme type SDF

Are only a few ways. Note that these ways all support you to append a subset using for, where clauses (ie: append ... for myDate < date()-10 ).
Cetin