London:body-class.js error on windows

=> Started proxy.
C:\Users\user\AppData\Local\.meteor\packages\meteor-tool\1.8.0_2\mt-os.windows.x86_64\dev_bundle\lib\node_modules\meteor-promise\promise_server.js:218
      throw error;
      ^

Error: ENOENT: no such file or directory, open 'C:\Users\user\AppData\Local\Temp\mt-jjo1vp.z11qi\web.browser\london:body-class.js'
    at Object.fs.openSync (fs.js:646:18)
    at Object.wrapper [as open] (C:\tools\fs\files.js:1609:35)
    at Object.files.readBufferWithLengthAndOffset (C:\tools\fs\files.js:1860:20)
    at C:\tools\isobuild\unibuild.js:122:26
    at Array.forEach (<anonymous>)
    at Function._.each._.forEach (C:\Users\user\AppData\Local\.meteor\packages\meteor-tool\1.8.0_2\mt-os.windows.x86_64\dev_bundle\lib\node_modules\underscore\underscore.js:79:11)
    at Function.fromJSON (C:\tools\isobuild\unibuild.js:119:7)
    at C:\tools\isobuild\isopack.js:921:33
    at Array.forEach (<anonymous>)
    at Function._.each._.forEach (C:\Users\user\AppData\Local\.meteor\packages\meteor-tool\1.8.0_2\mt-os.windows.x86_64\dev_bundle\lib\node_modules\underscore\underscore.js:79:11)
    at Isopack._loadUnibuildsFromPath (C:\tools\isobuild\isopack.js:908:7)
    at _.each (C:\tools\packaging\tropohouse.js:521:21)
    at Array.forEach (<anonymous>)
    at Function._.each._.forEach (C:\Users\user\AppData\Local\.meteor\packages\meteor-tool\1.8.0_2\mt-os.windows.x86_64\dev_bundle\lib\node_modules\underscore\underscore.js:79:11)
    at buildmessage.enterJob (C:\tools\packaging\tropohouse.js:520:13)
    at Object.enterJob (C:\tools\utils\buildmessage.js:388:12)
    at C:\tools\packaging\tropohouse.js:515:22
    at Object.enterJob (C:\tools\utils\buildmessage.js:388:12)
    at Object.download (C:\tools\packaging\tropohouse.js:427:20)
    at C:\tools\packaging\tropohouse.js:613:18
    at enterJobAsync.then (C:\tools\utils\buildmessage.js:609:21)
    at C:\Users\user\AppData\Local\.meteor\packages\meteor-tool\1.8.0_2\mt-os.windows.x86_64\dev_bundle\lib\node_modules\meteor-promise\fiber_pool.js:43:40
 => awaited here:
    at Promise.await (C:\Users\user\AppData\Local\.meteor\packages\meteor-tool\1.8.0_2\mt-os.windows.x86_64\dev_bundle\lib\node_modules\meteor-promise\promise_server.js:60:12)
    at Object.forkJoin (C:\tools\utils\buildmessage.js:604:10)
    at exports.Tropohouse.downloadPackagesMissingFromMap (C:\tools\packaging\tropohouse.js:609:18)
    at C:\tools\project-context.js:836:25
    at Object.enterJob (C:\tools\utils\buildmessage.js:388:12)
    at C:\tools\project-context.js:835:20
    at C:\tools\packaging\catalog\catalog.js:100:5
    at Object.capture (C:\tools\utils\buildmessage.js:283:5)
    at Object.catalog.runAndRetryWithRefreshIfHelpful (C:\tools\packaging\catalog\catalog.js:99:31)
    at ProjectContext._downloadMissingPackages (C:\tools\project-context.js:834:13)
    at C:\tools\project-context.js:300:9
    at Object.enterJob (C:\tools\utils\buildmessage.js:388:12)
    at ProjectContext._completeStagesThrough (C:\tools\project-context.js:290:18)
    at Profile.run (C:\tools\project-context.js:282:12)
    at Function.run (C:\tools\tool-env\profile.js:490:12)
    at ProjectContext.prepareProjectForBuild (C:\tools\project-context.js:281:13)
    at C:\tools\runners\run-app.js:544:29
    at Object.capture (C:\tools\utils\buildmessage.js:283:5)
    at bundleApp (C:\tools\runners\run-app.js:543:31)
    at AppRunner._runOnce (C:\tools\runners\run-app.js:610:35)
    at AppRunner._fiber (C:\tools\runners\run-app.js:908:28)
    at C:\tools\runners\run-app.js:398:12

The london:body-class package contains a file london:body-class.js. However, colons are not allowed in Windows.

You could try raising an issue on GitHub, but as this package no longer seems to be maintained, the best plan would be to fork-and-fix if you want to use it.