Flex builder 4 unknown error in xml file?

Question

Here is the error that the Flex builder shows:

Unknown error generating output application.xml files. Check the Eclipse error log for more details.    /Day View/src/view  Unknown AIR application.xml Problem DayView-app.xml

and here is this xml file that is automatically generated by the Flex builder but gives an unknown erreor:

<!-- The application identifier string, unique to this application. Required. -->
<id>DayView</id>

<!-- Used as the filename for the application. Required. -->
<filename>DayView</filename>

<!-- The name that is displayed in the AIR application installer. 
     May have multiple values for each language. See samples or xsd schema file. Optional. -->
<name>DayView</name>

<!-- An application version designator (such as "v1", "2.5", or "Alpha 1"). Required. -->
<version>v1</version>

<!-- Description, displayed in the AIR application installer.
     May have multiple values for each language. See samples or xsd schema file. Optional. -->
<!-- <description></description> -->

<!-- Copyright information. Optional -->
<!-- <copyright></copyright> -->

<!-- Settings for the application initial window. Required. -->
<initialWindow>
    <!-- The main SWF or HTML file of the application. Required. -->
    <!-- Note: In Flex Builder, the SWF reference is set automatically. -->
    <content>[This value will be overwritten by Flash Builder in the output app.xml]</content>

    <!-- The title of the main window. Optional. -->
    <!-- <title></title> -->

    <!-- The type of system chrome to use (either "standard" or "none"). Optional. Default standard. -->
    <!-- <systemChrome></systemChrome> -->

    <!-- Whether the window is transparent. Only applicable when systemChrome is none. Optional. Default false. -->
    <!-- <transparent></transparent> -->

    <!-- Whether the window is initially visible. Optional. Default false. -->
    <!-- <visible></visible> -->

    <!-- Whether the user can minimize the window. Optional. Default true. -->
    <!-- <minimizable></minimizable> -->

    <!-- Whether the user can maximize the window. Optional. Default true. -->
    <!-- <maximizable></maximizable> -->

    <!-- Whether the user can resize the window. Optional. Default true. -->
    <!-- <resizable></resizable> -->

    <!-- The window initial width. Optional. -->
    <!-- <width></width> -->

    <!-- The window initial height. Optional. -->
    <!-- <height></height> -->

    <!-- The window initial x position. Optional. -->
    <!-- <x></x> -->

    <!-- The window initial y position. Optional. -->
    <!-- <y></y> -->

    <!-- The window minimum size, specified as a width/height pair, such as "400 200". Optional. -->
    <!-- <minSize></minSize> -->

    <!-- The window initial maximum size, specified as a width/height pair, such as "1600 1200". Optional. -->
    <!-- <maxSize></maxSize> -->
</initialWindow>

<!-- The subpath of the standard default installation location to use. Optional. -->
<!-- <installFolder></installFolder> -->

<!-- The subpath of the Programs menu to use. (Ignored on operating systems without a Programs menu.) Optional. -->
<!-- <programMenuFolder></programMenuFolder> -->

<!-- The icon the system uses for the application. For at least one resolution,
     specify the path to a PNG file included in the AIR package. Optional. -->
<!-- <icon>
    <image16x16></image16x16>
    <image32x32></image32x32>
    <image48x48></image48x48>
    <image128x128></image128x128>
</icon> -->

<!-- Whether the application handles the update when a user double-clicks an update version
of the AIR file (true), or the default AIR application installer handles the update (false).
Optional. Default false. -->
<!-- <customUpdateUI></customUpdateUI> -->

<!-- Whether the application can be launched when the user clicks a link in a web browser.
Optional. Default false. -->
<!-- <allowBrowserInvocation></allowBrowserInvocation> -->

<!-- Listing of file types for which the application can register. Optional. -->
<!-- <fileTypes> -->

    <!-- Defines one file type. Optional. -->
    <!-- <fileType> -->

        <!-- The name that the system displays for the registered file type. Required. -->
        <!-- <name></name> -->

        <!-- The extension to register. Required. -->
        <!-- <extension></extension> -->

        <!-- The description of the file type. Optional. -->
        <!-- <description></description> -->

        <!-- The MIME content type. -->
        <!-- <contentType></contentType> -->

        <!-- The icon to display for the file type. Optional. -->
        <!-- <icon>
            <image16x16></image16x16>
            <image32x32></image32x32>
            <image48x48></image48x48>
            <image128x128></image128x128>
        </icon> -->

    <!-- </fileType> -->
<!-- </fileTypes> -->

Answer 1

just ran into the same problem. after some googling did not find any answer.

then after examining the eclipse editior an error log was found: d. window> show view> other> select error log

Answer 2

increase heap size, this can be a problem due to heap size starting up

eclipse/plugins/org.eclipse.equinox.launcher_1.2.0.v20110502.jar
--launcher.library
eclipse/plugins/org.eclipse.equinox.launcher.win32.win32.x86_1.1.100.v20110502
--launcher.defaultAction
openFile
-nl
en_US
-vmargs
-Xms1024m
-Xmx1024m
-XX:MaxPermSize=256m
-XX:PermSize=64m
-Dorg.eclipse.equinox.p2.reconciler.dropins.directory=eclipse/dropins
-Declipse.application=com.adobe.flexbuilder.standalone.FlashBuilderApplication