PDF conversion on Linux/Java very slow

I have a PDF document that converts to PNG fine on Windows, but doesn't work on Linux - it's very slow, and doesn't generate any text.  I see that there are instructions for adding TrueType fonts for Aspose.Words, is there a similar procedure for Aspose.Pdf?  I do have the dejavu font installed...

Would the missing fonts be the cause of the slowdown?

Here's the stack trace where it always seems to always be stuck:

 - java.util.HashMap.createEntry(int, java.lang.Object, java.lang.Object, int) @bci=15, line=897 (Compiled frame)
 - java.util.HashMap.addEntry(int, java.lang.Object, java.lang.Object, int) @bci=65, line=884 (Compiled frame)
 - java.util.HashMap.put(java.lang.Object, java.lang.Object) @bci=137, line=505 (Compiled frame)
 - java.util.jar.Attributes.put(java.lang.Object, java.lang.Object) @bci=12, line=148 (Compiled frame)
 - java.util.jar.Attributes.putValue(java.lang.String, java.lang.String) @bci=10, line=168 (Compiled frame)
 - java.util.jar.Attributes.read(java.util.jar.Manifest$FastInputStream, byte[]) @bci=301, line=421 (Compiled frame)
 - java.util.jar.Manifest.read(java.io.InputStream) @bci=291, line=251 (Compiled frame)
 - sun.security.util.SignatureFileVerifier.processImpl(java.util.Hashtable, java.util.List) @bci=20, line=252 (Compiled frame)
 - sun.security.util.SignatureFileVerifier.process(java.util.Hashtable, java.util.List) @bci=9, line=239 (Interpreted frame)
 - java.util.jar.JarVerifier.processEntry(sun.security.util.ManifestEntryVerifier) @bci=387, line=317 (Interpreted frame)
 - java.util.jar.JarVerifier.update(int, byte[], int, int, sun.security.util.ManifestEntryVerifier) @bci=39, line=228 (Compiled frame)
 - java.util.jar.JarFile.initializeVerifier() @bci=143, line=348 (Compiled frame)
 - java.util.jar.JarFile.getInputStream(java.util.zip.ZipEntry) @bci=25, line=415 (Interpreted frame)
 - sun.net.www.protocol.jar.JarURLConnection.getInputStream() @bci=88, line=162 (Interpreted frame)
 - java.net.URL.openStream() @bci=4, line=1037 (Interpreted frame)
 - org.apache.catalina.loader.WebappClassLoader.findLoadedResource(java.lang.String) @bci=47, line=2689 (Interpreted frame)
 - org.apache.catalina.loader.WebappClassLoader.getResourceAsStream(java.lang.String) @bci=47, line=1101 (Interpreted frame)
 - com.aspose.pdf.internal.p437.z16.m2(java.lang.String) @bci=14 (Compiled frame)
 - com.aspose.pdf.internal.p437.z16.m9() @bci=454 (Interpreted frame)
 - com.aspose.pdf.internal.p437.z16.m8() @bci=15 (Interpreted frame)
 - com.aspose.pdf.internal.p437.z16.m7() @bci=8 (Interpreted frame)
 - com.aspose.pdf.internal.p437.z16.m1() @bci=19 (Interpreted frame)
 - com.aspose.pdf.internal.p437.z29.m9() @bci=93 (Interpreted frame)
 - com.aspose.pdf.internal.p437.z29.m16() @bci=1 (Interpreted frame)
 - com.aspose.pdf.internal.p427.z3.m1(com.aspose.pdf.internal.p413.z4) @bci=11 (Interpreted frame)
 - com.aspose.pdf.internal.p416.z40.m2(com.aspose.pdf.internal.p413.z4) @bci=2 (Interpreted frame)
 - com.aspose.pdf.internal.p416.z40.m4(com.aspose.pdf.internal.p413.z4) @bci=14 (Interpreted frame)
 - com.aspose.pdf.internal.p416.z13.m2(com.aspose.pdf.internal.p413.z4, com.aspose.pdf.internal.p236.z17) @bci=89 (Interpreted frame)
 - com.aspose.pdf.internal.p416.z13.m1(com.aspose.pdf.internal.p395.z6, com.aspose.pdf.internal.p399.z11, com.aspose.pdf.internal.p489.z13, com.aspose.pdf.internal.p413.z4[]) @bci=73 (Interpreted frame)
 - com.aspose.pdf.devices.z4.m1(com.aspose.pdf.internal.p413.z4[]) @bci=758 (Interpreted frame)
 - com.aspose.pdf.devices.z4.m1() @bci=13 (Interpreted frame)
 - com.aspose.pdf.devices.ImageDevice.m1(com.aspose.pdf.Page) @bci=56 (Interpreted frame)
 - com.aspose.pdf.devices.PngDevice.processInternal(com.aspose.pdf.Page, com.aspose.pdf.internal.p249.z41) @bci=2 (Interpreted frame)
 - com.aspose.pdf.devices.PngDevice.process(com.aspose.pdf.Page, java.io.OutputStream) @bci=11 (Interpreted frame)