Logs flyby - j.l.NPE of unknown origin

2010-03-04 18:39:40,919 INFO [TP-Processor20] [atlassian.confluence.status.SystemErrorInformationLogger] writeToLog
Request Unique ID : 5e8b334f-2e91-49ab-abe9-ccf8bea43266
--------------------------
JVM Stats
--------------------------
allocatedHeap = 1461125120
availablePermGen = 82086160
usedMemory = 810449112
totalMemory = 1461125120
freeMemory = 650676008
maxPermGen = 268435456
usedPermGen = 186349296
freeMemoryInMegabytes = 620
freeAllocatedHeap = 650676008
availableHeap = 650676008
usedMemoryInMegabytes = 772
maxHeap = 1461125120
usedHeap = 810449112
totalMemoryInMegabytes = 1393
--------------------------
Request Information
--------------------------
URL: https://qa-eac.atlassian.com/500page.jsp
Scheme: https
Server: qa-eac.atlassian.com
Port: 443
URI: /500page.jsp
Context Path:
Servlet Path: /500page.jsp
Path Info: null
Query String: version=1&modificationDate=
--------------------------
Attributes
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javax.servlet.forward.request_uri: /download/thumbnails/1770946853/bookmarks.png
javax.servlet.forward.context_path:
javax.servlet.forward.servlet_path: /download
javax.servlet.forward.path_info: /500page.jsp
javax.servlet.forward.query_string: version=1&modificationDate=
os_securityfilter_already_filtered: true
atlassian.core.seraph.original.url: /download/thumbnails/1770946853/bookmarks.png?version=1&modificationDate=
javax.servlet.error.status_code: 500
javax.servlet.error.servlet_name: file-server
com.atlassian.gzipfilter.GzipFilter_already_filtered: true
loginfilter.already.filtered: true
com.atlassian.confluence.web.ConfluenceJohnsonFilter_already_filtered: true
Confluence-Request-Time: 1267749580830
javax.servlet.error.message:
com.atlassian.core.filters.HeaderSanitisingFilter_already_filtered: true
__sitemesh__filterapplied: true
javax.servlet.error.exception: java.lang.NullPointerException
javax.servlet.error.request_uri: /download/thumbnails/1770946853/bookmarks.png
--------------------------
Parameters
--------------------------
modificationDate :
version : 1
caused by: java.lang.NullPointerException
at com.atlassian.core.util.thumbnail.Thumber.determineScaleSize(Thumber.java:235)