diff --git a/src/main/java/info/bukova/isspst/security/IsspstPermissionEvaluator.java b/src/main/java/info/bukova/isspst/security/IsspstPermissionEvaluator.java
index 574e30c1..4237338a 100644
--- a/src/main/java/info/bukova/isspst/security/IsspstPermissionEvaluator.java
+++ b/src/main/java/info/bukova/isspst/security/IsspstPermissionEvaluator.java
@@ -35,11 +35,14 @@ public class IsspstPermissionEvaluator implements PermissionEvaluator {
 			
 			perm += "_" + moduleId;
 			
-			for (Role r : perms) {
-				if (r.getAuthority().equals(perm)) {
+			for (int i = 0; i < perms.size(); i++) {
+				if (!(perms.get(i) instanceof Role)) {
+					return false;
+				}
+				if (perms.get(i).getAuthority().equals(perm)) {
 					return true;
 				}
-				if (r.getAuthority().equals(Constants.ROLE_ADMIN)) {
+				if (perms.get(i).getAuthority().equals(Constants.ROLE_ADMIN)) {
 					return true;
 				}
 			}