diff --git a/src/opt/hdf5/lib/h5_table.cc b/src/opt/hdf5/lib/h5_table.cc
index 63e7c36..d05e3de 100644
--- a/src/opt/hdf5/lib/h5_table.cc
+++ b/src/opt/hdf5/lib/h5_table.cc
@@ -102,9 +102,9 @@ namespace CNORXZ
 	    const Int compress = 0;
 	    mRecords = CRangeFactory(n).create();
 	    Vector<const char*> fields(mFields->size());
-	    auto fr = std::dynamic_pointer_cast<URange<String>>(mFields);
+	    auto fr = std::dynamic_pointer_cast<URange<FieldID>>(mFields);
 	    for(auto fi = fr->begin(); fi != fr->end(); ++fi){
-		fields[fi.lex()] = (*fi).c_str();
+		fields[fi.lex()] = (*fi).second.c_str();
 	    }
 	    const herr_t err = H5TBmake_table
 		(mName.c_str(), mParent->id(), mName.c_str(), mFields->size(), mRecords->size(), dsize,