Unable to export to word when page contains unresolved icon URLs

Confluence is unable to export to word a page that contains a jira issue link that uses a different icon other than the default.

The use case was the following:
1) Setup a Confluence 5.5.3 and JIRA 6.2.7 (5.1.7 also have failed).
2) Installed the Agile plugin on JIRA and created a sample project.
3) Went to JIRA -> administration -> issues and edited the epic issue type.
4) Changed the issue icon:

From this: /images/icons/ico_epic.png

To this: /download/resources/com.pyxis.greenhopper.jira:greenhopper-webactions/images/ico_epic.png

5) Set the Confluence and jira application links
6) Create a Confluence page and insert a jira issue link (+ -> jira issue -> recently viewed -> select an epic issue link)
7) Save the page and try to export to word.

The page won't be displayed and the following appears in Confluence logs:

 [http-8090-5] [[Standalone].[localhost].[/].[exportword]] log Servlet.service() for servlet exportword threw exception
java.lang.NullPointerException
at com.atlassian.confluence.servlet.ExportWordPageServer.createInputStreamFromRelativeUrl(ExportWordPageServer.java:426)
at com.atlassian.confluence.servlet.ExportWordPageServer.extractImagesFromPage(ExportWordPageServer.java:363)
at com.atlassian.confluence.servlet.ExportWordPageServer.outputWordDocument(ExportWordPageServer.java:233)
at com.atlassian.confluence.servlet.ExportWordPageServer.service(ExportWordPageServer.java:172)
at com.atlassian.confluence.servlet.SpringManagedServlet.service(SpringManagedServlet.java:64)

The page can still be exported to PDF, however if you look the exported file, the icon for the epic link is missing.

This was noted for pages exported that uses the PlantUML plugin as well.

Workaround

The workaround for pages exports that fails on JIRA issues icons is to change the icon to the other URL path and refresh confluence page to be able to export to word.

Another workaround would be to remove the "Issue Type" from the "Display Options", before adding the issue on the Confluence page, as it would then allow the export.