A SOAP::Fault story, or how is SOAP is making me nuts

Hi all: I have a working SOAP server on a host. But the same SOAP server running on a different host I'm installing for testing purposes, fails to run with this nice Fault: <args xsi:type="SOAP-ENC:Array" SOAP-ENC:arrayType="xsd:anyType[5]" SOAP-ENC:offset="[0]"> <item xsi:type="xsd:string">xml_set_object(): supplied argument is not a valid XML Parser resource</item> <item xsi:type="xsd:string">Server</item> <item/> <item/> <item xsi:type="xsd:string">Errno: 2 Filename: /usr/local/apache-1.3.31/htdocs/qreader-kernel/kernel/soap/frules.lib.php Lineno: 45 Even when the xml_set_object is called with the @ operator prepended. Differences: PHP 4.3.2 on the working fine box; PHP 4.3.9 on the non working box. Another box: WinXP with PHP 4.3.4 (and both the mmcache and Zend's optimizers installed) crashes with a nice Access Violation message, when I try to make RPC to the same SOAP server. The faulting lines: // Filter_XMLReader extends XML_Parser $xp = new Filter_XMLReader(); @xml_set_object($xp->parser, $xp); Any ideas? Manuel.