diff --git a/compiler2/main.cc b/compiler2/main.cc
index f6915cb41404f39285f46e663d1ef7d4b88cfff5..a9143eb202b71174e186bbf6a9d964257ccc3c64 100644
--- a/compiler2/main.cc
+++ b/compiler2/main.cc
@@ -930,7 +930,7 @@ int main(int argc, char *argv[])
   boolean ttcn3_module = is_ttcn3_module(module->file_name, fp, NULL);
   if (asn1_module) {
     if (!is_valid_asn1_filename (module->file_name)) {
-      ERROR("The file name '%s' (without suffix) shall be identical to the module name '%s'.\n"
+      ERROR("The file name `%s' (without suffix) shall be identical to the module name `%s'.\n"
             "If the name of the ASN.1 module contains a hyphen, the corresponding "
             "file name shall contain an underscore character instead.", module->file_name, module_name);
     }
diff --git a/compiler2/makefile.c b/compiler2/makefile.c
index 11ea3f3649dda6a6e990857d71bad4b65de12d4d..ebed29f18b43927d00ad936b873e8aea264c7999 100644
--- a/compiler2/makefile.c
+++ b/compiler2/makefile.c
@@ -4041,7 +4041,7 @@ static void generate_makefile(size_t n_arguments, char *arguments[],
            if (is_valid_asn1_filename(file_name)) {
              add_asn1_module(&makefile, file_name, module_name);
            } else {
-               ERROR("The file name '%s' (without suffix) shall be identical to the module name '%s'.\n"
+               ERROR("The file name `%s' (without suffix) shall be identical to the module name `%s'.\n"
                      "If the name of the ASN.1 module contains a hyphen, the corresponding "
                      "file name shall contain an underscore character instead.", file_name, module_name);
                Free(module_name);