OpenSP: Cannot generate system identifier for general entity ...
An entity reference was found in the document, but there is no reference by that name defined. Often this is caused by misspelling the reference name, unencoded ampersands, or by leaving off the trailing semicolon (;). The most common cause of this error is unencoded ampersands in URLs as described by the WDG in Ampersands in URLs.
All special characters in the HREF attribute should be encoded. "&" is a reserved character beginning an entity. (ex: ). Ampersands in HREF field should be encoded as the equivalent entity "&", even when used as a separator for parameters in the URL. Also keep in mind that named entity references are case-sensitive; &Aelig; and æ are different characters.
If this error appears in some markup generated by PHP's session handling code, this article has explanations and solutions to your problem.
Replace "&" with "&".
- W3C spec: http://www.w3.org/TR/html4/appendix/notes.html#h-B.2.2
- W3C CDATA: http://www.w3.org/TR/html4/types.html#type-cdata
- HtmlHelp: http://www.htmlhelp.com/tools/validator/problems.html#amp
- How to compose the HREF to mimic a FORM submission: http://www.htmlpedia.org/wiki/FormSubmissionByURL