diff --git a/src/pulp/pulp.py b/src/pulp/pulp.py
index 898a36e..f7aca00 100644
--- a/src/pulp/pulp.py
+++ b/src/pulp/pulp.py
@@ -851,7 +851,7 @@ class LpConstraint(LpAffineExpression):
 
     def __str__(self):
         s = LpAffineExpression.__str__(self, 0)
-        if self.sense:
+        if self.sense is not None:
             s += " " + LpConstraintSenses[self.sense] + " " + str(-self.constant)
         return s
 
diff --git a/src/pulp/solvers.py b/src/pulp/solvers.py
index a59ea54..a5e8726 100644
--- a/src/pulp/solvers.py
+++ b/src/pulp/solvers.py
@@ -1330,7 +1330,7 @@ class COIN_CMD(LpSolver_CMD):
             cmds += "branch "
         else:
             cmds += "initialSolve "
-        cmds += "printingOptions rows "
+        cmds += "printingOptions all "
         cmds += "solution "+tmpSol+" "
         if self.msg:
             pipe = None
@@ -1964,7 +1964,7 @@ class PYGLPK(LpSolver):
         #import the model into the global scope
         global glpk
         import glpk.glpkpi as glpk
-    except ImportError:
+    except:
         def available(self):
             """True if the solver is available"""
             return False