Zotero problem opening PDF, Firefox 19 and pdf.js

Error report number 402770691

Zotero has problem with Firefox 19 too.
On clicking a PDF attachments from zotero opens blank grey page.
Firefox, using pdf.js, can show other PDF. Zotero's PDF attachments are okay, they all open with external viewer.
System Mac OSX 10.8.2.

Error report number 402770691
Following error message is generated, in case it helps :
[JavaScript Error: "this.docShell is null" {file: "chrome://global/content/bindings/browser.xml" line: 323}]
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