You may want to create a class which contains the fields for each table that are autoincrement. Step through the class for the table and if any fields are excluded due to autoincrement, then exclude them in the gather statement as below:

store 'excludedfieldname' TO exfields
gather MEMVAR FIELDS EXCEPT &exfields

You can also use afields() and check for 'I' in the 2nd column and a value greater than 0 in 17 and 18.
(Not tested)

=AFIELDS(amyfields,'mytablealias')
exfields = ''
FOR i = 1 to ALEN(amyfields,1)
    IF amyfields(i,2) = 'I' .and. amyfields(i,18) > 0
       ? amyfields(i,1)
       ? amyfields(i,2)
       ? amyfields(i,17)
       ? amyfields(i,18)
       IF !EMPTY(exfields)
          STORE exfields + ',' + amyfields(i,1) TO exfields
       ELSE
          STORE amyfields(i,1) TO exfields
       ENDIF
    ENDIF
ENDFOR
IF !EMPTY(exfields)
    GATHER MEMVAR FIELDS EXCEPT &exfields
ELSE
    GATHER MEMVAR
ENDIF

See afields() under VFP HELP.

>Hello to all
>
>I am having a very sporadic problem. I have a table with an autoIncrement primary key named INVTYPEPK. On occasion,
>The error:
>
> "Field INVTYPEPK is read only”
>
>The code:
>
> GATHER MEMVAR MEMO && FIELDS EXCEPT invTypePK
>
>We have granted full-rights to the user, but the error still occurs sporadically. It has yet to occur with any other users, but the routine is used rarely by others.
>
>Any ideas??
>
>Thanks in advance