Problem: Connecting to a remote Oracle Server with PHP4/ WindowsNT/Apache,extension Oracle

Description:
1)Configuration:
Oracle client 7.3
Apache 1.3.12
php version 4.0.3pl1
server api: cgi
system: windows NT 4.0
activated extension: Oracle(installation of php_oracle.ddl good !, tested) 
	
2)I have setup the sqlnet.ora and tnsnames.ora files to point to the location of the remote DB:

MARP.WORLD =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = bca02bruqldb01)(PORT = 1521))
    (CONNECT_DATA = (SID = MARP))
  )

3)With a query tool like WinSQL or MSACCESS the connection to the database works perfect!!!

4)When a try to connect in a phpscript it doesn't work anymore!!
     $conn=Ora_Logon("USERNAME@MARP","password");
	
I get the error:
Oracle: Connection Failed: ORA-12154: TNS:could not resolve service name 

5) I also get the following error file SQLnetin the log:
***********************************************************************
Fatal OSN connect error 12154, connecting to:
 MARP

  VERSION INFORMATION:
	TNS for 32-bit Windows: Version 2.3.4.0.0 - Production
  Time: 23-OCT-00 09:47:05
  Tracing not turned on.


***********************************************************************
Fatal OSN connect error 12547, connecting to:
 (DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=BEQ)(PROGRAM=oracle80)(ARGV0=oracle80ORCL)(ARGS='(DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))')))(CONNECT_DATA=(SID=ORCL)(CID=(PROGRAM=php.exe)(HOST=PCINF990009115)(USER=KJC6600))))

  VERSION INFORMATION:
	TNS for 32-bit Windows: Version 2.3.4.0.0 - Production
	Oracle Bequeath NT Protocol Adapter for 32-bit Windows: Version 2.3.4.0.0 - Production
  Time: 23-OCT-00 09:47:06
  Tracing not turned on.
  Tns error struct:
    nr err code: 12206
    TNS-12206: TNS:received a TNS error during navigation
    ns main err code: 12547
    TNS-12547: TNS:lost contact
    ns secondary err code: 12560
    nt main err code: 517
    TNS-00517: Lost contact
    nt secondary err code: 0
    nt OS err code: 0

6) What is the solution ?
remark: I have similar problems with ODBC !!!!!

Please give in detail the steps to implement to make it work. I tried already several things.
Give a clear answer !!!!!!

7)Supplementary information:
I also tried to define environment variables for oracle in the httpd.conf

# Apache Oracle environment variables

SetEnv ORACLE_HOME "d:/orant"
SetEnv TNS_ADMIN "d:/orant/network/admin"

But nothing works !!

When I also set the environment variable ORACLE_SID
SetEnv ORACLE_SID "MARP"

Then I connect with:  $conn=Ora_Logon("USERNAME","password");

It don't work and I get another error:

ORA-03121 no interface driver connected - function not performed 

explanation of Oracle for this error:

Cause: This message occurs usually because the SQL*Net driver is not loaded into memory or there is a mismatch of the version of the driver. A user program linked with an obsolete library may also cause this message. Only programs provided by Oracle Corporation should use this interface.  
Action: If the message occurred during use of a program provided by Oracle Corporation, contact customer support. If a user program caused the message, relink the program with current versions of the Oracle libraries.