Yes, it is; but you need to make sure the path is a full valid URL. So for example:
C:\Path\To\Some file.iok
should be:
file://C:/Path/To/Some%20file.iok

(note the space converted to %20, and the forward slashes).

Andrew - An alternative to Web Start for this kind of internal network deployment is the custom JAR option. This option enables you to deploy a combination of your IOK data file and Viewer bundled as custom JAR rather than using the Web Start JNLP link.

This option is being made more visible given its usefulness…it is currently found here:

Settings > Advanced > Miscellaneous > Create Custom JAR

The result is just a single .jar file like any other, and this option allows you to deliver the data file and (own-branded licensing permitting) Viewer together ...without the end user having to install anything, just like Web Start.

The inputs required to be entered to create a custom JAR are:

Source JAR file: this the version of the Omniscope Viewer you want to use. If you leave this optional space blank, Omniscope will automatically download the latest Omniscope Viewer from our website and use that (default).

IOK file: This is the actual IOK data file you want to publish/share…i.e. MyConfiguredDataFile.iok

Output JAR file: This the full path to the output location + file name where the final output of the process is created…i.e. …/Desktop/MyBundledDataViewer.jar

This output .JAR file should be shareable on SharePoint, and via folder-sharing services like DropBox, but will be too large to attach to e-mail.

We've fixed the server error so regular file paths should now work, also.