PDI/Spoon Won't Run Transformations on Centos 7

I started using PDI in a new environment with below configuration. Spoon started normally and I was able to create/edit transformations and connections without any problem. But, the run, pause, and stop buttons on the toolbar were all enabled and clicking on any one of them did nothing. I was not able to run a transformation through spoon.

PDI 5.2 (pdi-ce-5.2.0.0-209)
Centos 7 (CentOS Linux release 7.0.1406 (Core))
XCFE desktop
java-1.7.0-openjdk.x86_64

After adding --sync in spoon.sh ("$_PENTAHO_JAVA" $OPT -jar "$STARTUP" --sync -lib $LIBPATH "${1+$@}"), I was able to see this error:

java.lang.NoClassDefFoundError: org/eclipse/swt/widgets/Control

I found another swt at http://archive.eclipse.org/eclipse/d.../index.php#SWT. There's probably a more appropriate place to get it. I replaced the file at data-integration/libswt/linux/x86_64/swt.jar.

I also removed the --sync from spoon.sh that I added because it continued to give the error.

But, now, I am able to open the run transformation dialog.