diff --git a/checkin_notes b/checkin_notes
index 6ec89c6391..82f35ee367 100644
--- a/checkin_notes
+++ b/checkin_notes
@@ -148,3 +148,9 @@ David  Jan 7 2007
 
     tools/
         backend_lib.C
+
+Rom    Jan 7 2007
+    - Empty strings cause CreateProcess to fail on parameter checks.
+    
+    clientgui/
+        BOINCGUIApp.cpp
diff --git a/clientgui/BOINCGUIApp.cpp b/clientgui/BOINCGUIApp.cpp
index 1533c81ede..2069826a94 100644
--- a/clientgui/BOINCGUIApp.cpp
+++ b/clientgui/BOINCGUIApp.cpp
@@ -605,6 +605,8 @@ void CBOINCGUIApp::StartupBOINCCore() {
         wxString strExecute = wxEmptyString;
 
 #if   defined(__WXMSW__)
+        LPTSTR  szExecute = NULL;
+        LPTSTR  szDataDirectory = NULL;
 
         // Append boinc.exe to the end of the strExecute string and get ready to rock
         strExecute.Printf(
@@ -624,15 +626,22 @@ void CBOINCGUIApp::StartupBOINCCore() {
         si.dwFlags = STARTF_USESHOWWINDOW;
         si.wShowWindow = SW_HIDE;
 
+        szExecute = (LPTSTR)strExecute.c_str();
+        if (GetDataDirectory().empty()) {
+            szDataDirectory = NULL;
+        } else {
+            szDataDirectory = (LPTSTR)GetDataDirectory().c_str();
+        }
+
         bProcessStarted = CreateProcess(
             NULL,
-            (LPTSTR)strExecute.c_str(),
+            szExecute,
             NULL,
             NULL,
             FALSE,
             CREATE_NEW_PROCESS_GROUP|CREATE_NO_WINDOW,
             NULL,
-            (LPTSTR)GetDataDirectory().c_str(),
+            szDataDirectory,
             &si,
             &pi
         );