Count(*) in the loop doesn't work and I really don't know why...

Question

Hello,
I can't figure out why the following doesn't work. I cannot debug for I do not have privileges on this server.
The execution always fails on bolded line. If I substitute the variable with the table name itself it works. The variable is properly populated in each of the iterations as I can see it by using dbms_output package. The small but may be important detail may be I am connected as user A but the tables are in the schema B. However I can list the tables and their columns in all_tab_cols view and there are synonyms made in my schema which allow me to access the B tables without prefixing them.
I get the error:
Error report:
ORA-00900: invalid SQL statement
ORA-06512: at line 26
00900. 00000 - "invalid SQL statement"
*Cause:   
*Action:
I ran out of ideas and I do not have access to any of the Oracle instance to be able to debug right now.
Variable type for v_tables is wrong? I do not have some magic privilege to use execute immediate with variable?
Oracle server has a bad day today?
The crap is 11.1.0.7 if it has anything to do with my problem.
Please help if you can.
Grzegorz
declare
v_number number := 646989;
v_current_table nvarchar2(50);
v_itemno number;
type t is table of nvarchar2(50);
v_tables t;
begin
dbms_output.put_line('Working...');
select table_name bulk collect into v_tables from all_tab_cols where column_name = 'ITEMNO' order by table_name;
for i in 1 .. v_tables.count loop
dbms_output.put_line('Number: ' || i);
v_current_table := v_tables(i);
<b>execute immediate 'select count(*) from ' || v_current_table || ' where itemno = :a' into v_itemno using v_number;</b>
if (v_itemno > 0) then
dbms_output.put_line('Current table contains specific ITEMNO: ' || v_current_table);
end if;
end loop;
end;

Answer 1

In SQL Plus run this and see what SQL is your code returning. Then execute the SQL individually.
set serveroutput on
declare
     v_number number := 646989;
     v_current_table nvarchar2(50);
     v_itemno number;
     type t is table of nvarchar2(50);
     v_tables t;
     lSqlString varchar2(20000);
begin
     select table_name
       bulk collect into v_tables
       from all_tab_cols
      where column_name = 'ITEMNO'
      order by table_name;
     for i in 1 .. v_tables.count loop
          v_current_table := v_tables(i);
          lSqlString := 'select count(*) from ' || v_current_table || ' where itemno = :a';
          dbms_output.put_line(lSqlString);
          --execute immediate  lSqlString into v_itemno using v_number;
     end loop;
end;