diff --git a/ext/htmlgrid/grid.c b/ext/htmlgrid/grid.c
index 56a50ef..6db471e 100644
--- a/ext/htmlgrid/grid.c
+++ b/ext/htmlgrid/grid.c
@@ -288,14 +288,16 @@ VALUE grid_width(self)
 VALUE grid_cat_attribute(pair, string)
 	VALUE pair, string;
 {
-	VALUE val;
+	VALUE val, tmp1, tmp2;
 	char *key, *value;
 	long len;
 	val = rb_ary_entry(pair, 1);
 	if(val == Qnil)
 		return string;
-	key = STR2CSTR(rb_ary_entry(pair, 0));
-	value = STR2CSTR(rb_funcall(val, rb_intern("to_s"), 0));
+  tmp1 = rb_ary_entry(pair, 0);
+	key = StringValuePtr(tmp1);
+  tmp2 = rb_funcall(val, rb_intern("to_s"), 0);
+	value = StringValuePtr(tmp2);
 	char attr[strlen(key) + strlen(value) + 5];
 	len = sprintf(attr, " %s=\"%s\"", key, value);
 	return rb_str_cat(string, attr, len);
@@ -333,8 +335,9 @@ VALUE grid_store_allowed_attribute(pair, attrs)
 	VALUE pair, attrs;
 {
 	char* key;
-
-	key = STR2CSTR(rb_ary_entry(pair, 0));
+  VALUE tmp;
+  tmp = rb_ary_entry(pair, 0);
+	key = StringValuePtr(tmp);
 	if( strcasecmp(key, "align") == 0 
 			|| strcasecmp(key, "class") == 0
 			|| strcasecmp(key, "colspan") == 0 
@@ -749,7 +752,7 @@ void grid_field_add_tag(cf, tagname)
 	cField * cf;
 	VALUE tagname;
 {
-	strcpy(cf->tag, STR2CSTR(tagname));
+	strcpy(cf->tag, StringValuePtr(tagname));
 }
 
 VALUE grid_add_tag(argc, argv, self)