Java exec doesn't work in 64 bit Windows-Collection of common programming errors

If its works as admin, but not as normal user then it is likely a problem with the privileges.

I strongly recommend to add some logging around the execution.

for example

Runtime runtime = Runtime.getRuntime();
Process convertProcess = runtime.exec(execProperties);

/** important; read the error stream before! invoke waitFor */
BufferedReader errorReader = new BufferedReader(
    new InputStreamReader(convertProcess.getErrorStream()));
try {
    StringBuilder errorMessage = new StringBuilder();
    String line = null;
    while ((line = errorReader.readLine()) != null) {
         errorMessage.append(line);
         errorMessage.append("\n");
    }

    int returnValue = convertProcess.waitFor();
    if (returnValue != 0) {
         handleNonZeroReturnValue(returnValue)
    }
} finally {
   errorReader.close();
}

I hope that helps you to “debug” the problem