First, let me say hello to the Joomlapolis community. It's a pleasure to work with you on this issue.
The first fix proposed by Beat does cause some problems. The most obvious is the disappearing admin menu. With that fix, the mos_components entries associated with the installed component contain corrupt data. There are two ways to recover. One is a clean reinstall of Mambo. The second is to remove the mos_components table entries associated with the component. The second method requires some familiarity with MySql and a utility such as PhpMyAdmin. You'll need to browse mos_components for the entries associated with your component. They'll be easy to spot. You'll find things like com_ instead of com_yourcomponent. And the component name may be missing or malformed. If you're not comfortable with modifying mos_components, ask someone to help. Or just do a fresh reinstall of Mambo.
Next, let me give you our proposed fix for the issue. It involves two modifications to administrator/includes/admin.php. IMPORTANT - Before starting, be sure to make a backup copy of admin.php. Also, be sure to use a plain text editor. If you're not comfortable making these modifications, ask someone for help. Ok, here goes. In two steps:
Step 1. - At about line 107 of administrator/includes/admin.php in function mosBasicXML::end_element():
Replace[code:1]$this->chardata = str_replace(' ampersand ', '&', $this->chardata);[/code:1]
With[code:1]$this->chardata = trim(str_replace(' ampersand ', '&', $this->chardata));[/code:1]
Step 2. - At about line 119 of administrator/includes/admin.php in function mosBasicXML::character_data():
Replace[code:1]$this->chardata .= trim($data);[/code:1]
With[code:1]$this->chardata .= $data;[/code:1]
IMPORTANT - You MUST do both modifications. Leaving out step 1 will cause the admin menu to disappear.
Please try this proposed fix and post back with your results. Thanks.
Al Warren
Mambo Core Development Team