Mysql error with user defined variable

[ipkwena]

...in design mode, i am able to activate a zeos query with the following sql statement:

SELECT
item, count(item) as entries,
(@row:=@row+1) AS row
FROM tbl_projcosts,
(SELECT @row:=0) AS row_count
group by projectno
order by
row

but when running the code, the application complains with this message:
"Error reading ZQuery2.SQL.Strings: Incorrect token followed by ':'"

when executing the statement in mySQL Query Browser, then a valid result set is returned.

i am using lazarus 0.9.28.2 beta; Zeos DBO 6.6.6; Mysql 5.1.47; OS = windows 7 starter.

any advise?