diff --git a/src/BroDoc.cc b/src/BroDoc.cc
index b20db727ff..9c617f78b3 100644
--- a/src/BroDoc.cc
+++ b/src/BroDoc.cc
@@ -85,8 +85,8 @@ void BroDoc::AddImport(const std::string& s)
 	if ( ext_pos != std::string::npos )
 		lname = lname.substr(0, ext_pos);
 
-	const char* full_filename = "<error>";
-	const char* subpath = "<error>";
+	const char* full_filename = NULL;
+	const char* subpath = NULL;
 	FILE* f = search_for_file(lname.c_str(), "bro", &full_filename, true,
 	                          &subpath);
 
diff --git a/src/Debug.cc b/src/Debug.cc
index 1b849fff7e..ea9c52f77e 100644
--- a/src/Debug.cc
+++ b/src/Debug.cc
@@ -142,7 +142,7 @@ int TraceState::LogTrace(const char* fmt, ...)
 
 	if ( ! loc.filename )
 		{
-		loc.filename = "<no filename>";
+		loc.filename = copy_string("<no filename>");
 		loc.last_line = 0;
 		}
 
@@ -735,7 +735,7 @@ string get_context_description(const Stmt* stmt, const Frame* frame)
 		loc = *stmt->GetLocationInfo();
 	else
 		{
-		loc.filename = "<no filename>";
+		loc.filename = copy_string("<no filename>");
 		loc.last_line = 0;
 		}