diff --git a/src/ChangeLog b/src/ChangeLog
index 0dc5809ceb..aa9e3b4502 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2005-01-20  Angus Leeming  <leeming@lyx.org>
+
+	* output_latex.C (TeXOnePar, TeXEnvironment): prevent crash when
+	printing diagnostic data by not dereferecing an iterator past the
+	end.
+
 2005-01-19  Asger Ottar Alstrup  <aalstrup@laerdal.dk>
 
 	* buffer.C (readHeader): use "&&" rather than "and".
@@ -7,7 +13,7 @@
 2005-01-19  Angus Leeming  <leeming@lyx.org>
 
 	* lyx_main.C (error_handler, init): protect SIGHUP with
-	#ifndef _WIN32 guards.
+	#ifdef SIGHUP guards.
 
 2005-01-19  Jean-Marc Lasgouttes  <lasgouttes@lyx.org>
 
diff --git a/src/output_latex.C b/src/output_latex.C
index 3fb0fe5d3d..d1ea46e50d 100644
--- a/src/output_latex.C
+++ b/src/output_latex.C
@@ -190,8 +190,9 @@ TeXEnvironment(Buffer const & buf,
 		texrow.newline();
 	}
 
-	lyxerr[Debug::LATEX] << "TeXEnvironment...done " << &*par << endl;
-	return par;  // ale970302
+	if (par != paragraphs.end() && lyxerr.debugging(Debug::LATEX))
+		lyxerr << "TeXEnvironment...done " << &*par << endl;
+	return par;
 }
 
 
@@ -416,7 +417,7 @@ paragraphs);
 		}
 	}
 
-	if (boost::next(pit) == const_cast<ParagraphList&>(paragraphs).end()
+	if (boost::next(pit) == paragraphs.end()
 	    && language->babel() != doc_language->babel()) {
 		// Since \selectlanguage write the language to the aux file,
 		// we need to reset the language at the end of footnote or
@@ -443,7 +444,9 @@ paragraphs);
 		texrow.newline();
 	}
 
-	lyxerr[Debug::LATEX] << "TeXOnePar...done " << &*boost::next(pit) << endl;
+	if (boost::next(pit) != paragraphs.end() &&
+	    lyxerr.debugging(Debug::LATEX))
+		lyxerr << "TeXOnePar...done " << &*boost::next(pit) << endl;
 	return ++pit;
 }