--- trunk/OOPSE/libmdtools/InitializeFromFile.cpp	2004/05/27 18:59:17	1203
+++ trunk/OOPSE/libmdtools/InitializeFromFile.cpp	2004/06/11 17:16:21	1268
@@ -518,6 +518,12 @@ char* InitializeFromFile::parseDumpLine(char* readLine
 
     qSqr = (q[0] * q[0]) + (q[1] * q[1]) + (q[2] * q[2]) + (q[3] * q[3]);
 
+    if (fabs(qSqr) < 1e-6) {
+      sprintf(painCave.errMsg,
+          "initial quaternion error (q0^2 + q1^2 + q2^2 + q3^2 ~ 0).\n");
+       return strdup(painCave.errMsg);
+    }
+    
     qLength = sqrt( qSqr );
     q[0] = q[0] / qLength;
     q[1] = q[1] / qLength;