diff --git a/src/com/xmlcalabash/library/XSLFormatter.java b/src/com/xmlcalabash/library/XSLFormatter.java
index 03959430..867b4205 100644
--- a/src/com/xmlcalabash/library/XSLFormatter.java
+++ b/src/com/xmlcalabash/library/XSLFormatter.java
@@ -78,9 +78,11 @@ public void run() throws SaxonApiException {
                     provider.initialize(runtime,step,options);
                     break;
                 } catch (NoClassDefFoundError ncdfe) {
+                    logger.debug("No FO processor class available: " + className);
                     pexcept = ncdfe;
                     provider = null;
                 } catch (Exception e) {
+                    logger.debug("Failed to instantiate FO processor class: " + className);
                     pexcept = e;
                     provider = null;
                 }