SQL Coding

I'm attempting to copy data from an Epicore server with multiple company
databases to another server. All this data will be placed in a single
table on the receiving server with the addition of an database identifier,
so that the receiving department will know, to which company the data
belongs. I have code that will dynamically create the SQL and then
execute it using EXEC (@SQL), and this works just fine acrosss multiple
databases. I've read in my Transact-SQL Programming book that using
EXEC() is not limited to 255 characters, but it still appears that my
dynamically created SQL is being shortened. The insert statement and the
select statement list each column, and here is that code:

SELECT @CMD = "INSERT ##APMaster(Company, timestamp, vendor_code,
pay_to_code, address_name,
short_name, addr1, addr2, addr3, addr4, addr5, addr6, addr_sort1,
addr_sort2, addr_sort3, address_type,
status_type, attention_name, attention_phone, contact_name, contact_phone,
tlx_twx, phone_1, phone_2,
tax_code, terms_code, fob_code, posting_code, location_code,
orig_zone_code, customer_code,
affiliated_vend_code, alt_vendor_code, comment_code, vend_class_code,
branch_code, pay_to_hist_flag,
item_hist_flag, credit_limit_flag, credit_limit, aging_limit_flag,
aging_limit, restock_chg_flag,
restock_chg, prc_flag, vend_acct, tax_id_num, flag_1099, exp_acct_code,
amt_max_check, lead_time,
doc_ctrl_num, one_check_flag, dup_voucher_flag, dup_amt_flag, code_1099,
user_trx_type_code, payment_code,
limit_by_home, rate_type_home, rate_type_oper, nat_cur_code,
one_cur_vendor, cash_acct_code, city, state,
postal_code, country, freight_code, url, note) SELECT '" + @DBName + "' AS
Company, timestamp, vendor_code,
pay_to_code, address_name, short_name addr1, addr2, addr3, addr4, addr5,
addr6,
addr_sort1, addr_sort2, addr_sort3, address_type, status_type,
attention_name, attention_phone, contact_name,
contact_phone, tlx_twx, phone_1, phone_2, tax_code, terms_code, fob_code,
posting_code, location_code,
orig_zone_code, customer_code, affiliated_vend_code, alt_vendor_code,
comment_code, vend_class_code,
branch_code, pay_to_hist_flag, item_hist_flag, credit_limit_flag,
credit_limit, aging_limit_flag,
aging_limit, restock_chg_flag, restock_chg, prc_flag, vend_acct,
tax_id_num, flag_1099, exp_acct_code,
amt_max_check, lead_time, doc_ctrl_num, one_check_flag, dup_voucher_flag,
dup_amt_flag, code_1099,
user_trx_type_code, payment_code, limit_by_home, rate_type_home,
rate_type_oper, nat_cur_code, one_cur_vendor,
cash_acct_code, city, state, postal_code, country, freight_code, url, note
FROM " + @DBName + "..APMaster"

Can anyone provide any insight to my problem?

TIA,
Chris