Can't load php3_oci8.dll !!!

Hi! I have php 3.0.17 on IIS 4 working as CGI. The binaries were downloaded from www.php.net. I also have Net8 client from Oracle 8.1.5 working (I can connect to the Oracle8 server via OLE DB, for example). The fact is that after uncommenting in php3.ini extension=php3_oci8.dll stopping and restarting IIS, this dll doesn't seem to load, because I get this: Fatal error: Call to unsupported or undefined function ocilogon() in ... My Oracle\bin directory is included in PATH environment variable, and I have even defined ORACLE_HOME and ORACLE_SID env. variables just in case. Other extensions (like php3_mssql70.dll) have loaded fine and I think we have all the client libraries. I've also tested with php 4.0.3pl1 as CGI and I get the same problem. What can it be? Thanks in advance. F J Ortiz Torre