Looks like maybe you're missing a few fields there. I don't have QB 6.0 available, but if you have the documentation then I'd suggest following it and creating an entry for every field even if it's empty. FWIW here's a sample for QuickBooks 2000 (this is wide, sorry about the horizontal scrolling):

!TRNS	TRNSID	TRNSTYP	DATE	ACCNT	NAME	CLASS	AMOUNT	DOCNUM	MEMO	CLEAR	TOPRINT	ADDR1	ADDR2	ADDR3	ADDR4	ADDR5	DUEDATE	TERMS	PAID	SHIPDATE
!SPL	SPLID	TRNSTYP	DATE	ACCNT	NAME	CLASS	AMOUNT	DOCNUM	MEMO	CLEAR	QNTY	PRICE	INVITEM	PAYMETH	TAXABLE	REIMBEX	EXTRA
!ENDTRNS
TRNS		INVOICE	08/30/1999	Accounts Receivable	JOHNDOE		17.80	350031		N	Y							Net 45 Days	N	08/30/1999
SPL		INVOICE	08/30/1999	Sales			-17.80			N		17.80	Product		N	NOTHING	
ENDTRNS
TRNS		INVOICE	08/30/1999	Accounts Receivable	JANEDOE		25.30	350032		N	Y							Net 45 Days	N	08/30/1999
SPL		INVOICE	08/30/1999	Sales			-25.30			N		25.30	Product		N	NOTHING	
ENDTRNS

>I work for a software developer who manufactures a VFP catalog management program and we would like to give our users the option to send sales transaction data to QuickBooks 6.0.
>
>I have read Intuit's knowledgebase and online help articles about the required file structure - so I created a basic test file to see if it would work:
>
>!TRNS TRNSTYPE ACCNT AMOUNT
>!SPL TRNSTYPE ACCNT AMOUNT
>!ENDTRNS
>TRNS INVOICE ACCOUNTS RECEIVABLE 100.00
>SPL INVOICE PRODUCT SALLES -95.00
>SPL INVOICE SALES TAX PAYABLE -5.00
>ENDTRANS
>
>It didn't - even though QuickBooks indicated that the file was imported, I did not see any change to the account balances.
>
>I was wondering if anyone might be intereseted in helping me get over the initial steps of this process? I think once I get the basic structure working I should be able to do the rest.
>
>Thanks in advance