diff --git a/python/obitools3/commands/grep.pyx b/python/obitools3/commands/grep.pyx
index c3555ec..e4ac80a 100644
--- a/python/obitools3/commands/grep.pyx
+++ b/python/obitools3/commands/grep.pyx
@@ -91,7 +91,7 @@ def addOptions(parser):
                        metavar="<ATTRIBUTE_NAME>",
                        help="Select records with the attribute <ATTRIBUTE_NAME> "
                             "defined (not set to NA value). "
-                            "Several -a options can be used on the same "
+                            "Several -A options can be used on the same "
                             "command line.")
     
     group.add_argument("-L", "--lmax",
diff --git a/src/build_reference_db.c b/src/build_reference_db.c
index c7c0c1c..ce593de 100755
--- a/src/build_reference_db.c
+++ b/src/build_reference_db.c
@@ -77,6 +77,7 @@ static inline ecotx_t* get_lca_from_merged_taxids(Obiview_p view, OBIDMS_column_
 {
 	ecotx_t* taxon = NULL;
 	ecotx_t* lca = NULL;
+	ecotx_t* lca1 = NULL;
 	int32_t taxid;
 	index_t taxid_idx;
 	int64_t taxid_str_idx;
@@ -108,10 +109,11 @@ static inline ecotx_t* get_lca_from_merged_taxids(Obiview_p view, OBIDMS_column_
 			else
 			{
 				// Compute LCA
+				lca1 = lca;
 				lca = obi_taxo_get_lca(taxon, lca);
 				if (lca == NULL)
 				{
-					obidebug(1, "\nError getting the last common ancestor of two taxa when building a reference database");
+					obidebug(1, "\nError getting the last common ancestor of two taxa when building a reference database, %d %d", taxid, lca1->taxid);
 					return NULL;
 				}
 			}
@@ -185,7 +187,7 @@ int build_reference_db(const char* dms_name,
 	matrix_view_name = strcpy(matrix_view_name, o_view_name);
 	strcat(matrix_view_name, "_matrix");
 
-	fprintf(stderr, "Aligning queries with reference database...\n");
+	fprintf(stderr, "Aligning sequences...\n");
 	if (obi_lcs_align_one_column(dms_name,
 								 refs_view_name,
 								 "",