"XmlException: Data at the root level is invalid." crash in LogUpgraders

[gbakeman]

Just yesterday I was installing mods for Fallout New Vegas, when today I opened FOMM and was prompted to "upgrade some of its files". Clicking OK, a dialog box saying Upgrade Error appears almost immediately, stating that "An error occurred while upgrading your log file." It then proceeds to save a brief stack trace, as follows:

Tuesday, July 19, 2016 - 10:25:26 PM
Fomm 0.14.11.12
OS version: Microsoft Windows NT 6.2.9200.0

System.Xml.XmlException: Data at the root level is invalid. Line 1, position 1.
at Fomm.BackgroundWorkerProgressDialog.System.IDisposable.Dispose()
at Fomm.InstallLogUpgraders.Upgrader.PerformUpgrade()
at Fomm.InstallLogUpgraders.InstallLogUpgrader.UpgradeInstallLog()
at Fomm.Program.Main(String[] args)

The file in question appears to be \FalloutNV\Install Info\InstallLog.xml. Here's a snippet of the file:

<installLog fileVersion="0.1.0.0">
  <modList>
    <mod name="ORIGINAL_VALUES" key="q0rwad0w" />
    <mod name="FOMM" key="itddpoie" />
    <mod name="nmcs textures nv medium pack part 1 of 2 for nmm-43135-1-0" key="wfv0pr3v">
      <version machineVersion="1.0.0.0">1.0</version>
    </mod>
    <mod name="nmcs textures nv medium pack part 2 of 2 for nmm -43135-1-0" key="wnzpwa5h">
      <version machineVersion="1.0.0.0">1.0</version>
    </mod>
  </modList>
  <dataFiles>
    <file path="textures\architecture\wasteland\alt_shack_texture.dds">
      <installingMods>
        <mod key="wfv0pr3v" />
      </installingMods>
    </file>
    <file path="textures\architecture\wasteland\alt_shack_texture_n.dds">
      <installingMods>
        <mod key="wfv0pr3v" />
      </installingMods>
    </file>
    <file path="textures\architecture\generic\apartmentpre01.dds">
      <installingMods>
        <mod key="wfv0pr3v" />
      </installingMods>
    </file>

...

Apparently, the fileVersion property is what's causing FOMM to prompt to upgrade. If I change its value to "0.2.0.0", FOMM, and the Package Manager, load just fine. But I wonder why a file I was working on just yesterday had version 0.1.0.0, when suddenly today I need version 0.2.0.0? And why does attempting to "upgrade" it cause this crash?