diff --git a/src/coins.cpp b/src/coins.cpp
index 9ffd10e33..1c6edcfe1 100644
--- a/src/coins.cpp
+++ b/src/coins.cpp
@@ -529,7 +529,10 @@ unsigned int CCoinsViewCache::GetCacheSize() const {
 const CTxOut &CCoinsViewCache::GetOutputFor(const CTxIn& input) const
 {
     const CCoins* coins = AccessCoins(input.prevout.hash);
+    fprintf(stderr, "GetOutputFor: input=%s", input.ToString().c_str());
+    fprintf(stderr, "GetOutputFor: prevout n=%d,txid=%s\n", input.prevout.n, input.prevout.hash.ToString().c_str());
     assert(coins && coins->IsAvailable(input.prevout.n));
+    fprintf(stderr, "GetOutputFor: IsAvailable\n");
     return coins->vout[input.prevout.n];
 }
 
diff --git a/src/coins.h b/src/coins.h
index d5503d4ba..4219e3dd6 100644
--- a/src/coins.h
+++ b/src/coins.h
@@ -245,6 +245,9 @@ public:
 
     //! check whether a particular output is still available
     bool IsAvailable(unsigned int nPos) const {
+        //fprintf(stderr,"IsAvailable(nPos=%d), vout.size()=%li, vout[%d].IsNull()=%d", nPos, vout.size(), nPos, vout[nPos].IsNull() );
+        //fprintf(stderr,"IsAvailable(nPos=%d), vout.size()=%li, vout[%d]=%d", nPos, vout.size(), nPos, vout[nPos] );
+        fprintf(stderr,"IsAvailable(nPos=%d), vout.size()=%li", nPos, vout.size() );
         return (nPos < vout.size() && !vout[nPos].IsNull());
     }