Problems connecting to oracle using PHP4

Hello freaks, I'm investigating a problem with the connectivity to a remote Oracle-8-DB with PHP4.02 under WinNT (PHP as cgi-filter under Xitami, Oracle Client via ODBC successfully installed). While connecting to the database works as described with PHP3 (no matter whether ODBC or OCI) with PHP4 (same skript) no single ethernet frame leaves my WinNT station in direction database. Phpinfo shows ODBC support (or OCI support respectively) loaded. PHP.INI is changed from best compatibility mode. The error messages are "Warning: SQL error: [Oracle][ODBC][Ora]Server rejected the connection., SQL state 08004 in SQLConnect in C:/Xitami/webpages/..." (ODBC) or "Warning: _oci_open_server: ORA-12154: TNS:The service name could not be resolved in C:/Xitami/webpages/..." (OCI), but remember that no attempt to connect over the network is done. Any hints are very welcome Andy