diff --git a/build/tools/wxwidgets.iss b/build/tools/wxwidgets.iss
index b07fcd5784..ad6cbe5d86 100644
--- a/build/tools/wxwidgets.iss
+++ b/build/tools/wxwidgets.iss
@@ -1,17 +1,23 @@
 ; Script generated by the Inno Setup Script Wizard.
 ; SEE THE DOCUMENTATION FOR DETAILS ON CREATING INNO SETUP SCRIPT FILES!
 
-#define INNODIR GetENV("INNO")
+#if GetEnv("INNO") != ""
+    #define WXW_DIR GetEnv("INNO")
+#else
+    #define WXW_DIR "..\.."
+#endif
 
 #if GetEnv("WXW_VER") == "SVN"
-    #define INFOFILE  GetENV("INNO") + "\BuildSVN.txt"
+    #define INFOFILE  WXW_DIR + "\BuildSVN.txt"
     #define WX_VERSION "SVN"
+#elif GetEnv("WXW_VER") != ""
+    #define INFOFILE WXW_DIR + "\docs\msw\install.txt"
+    #define WX_VERSION GetEnv("WXW_VER")
 #else
-    #define INFOFILE GetENV("INNO") + "\docs\msw\install.txt"
-    #define WX_VERSION GetENV("WXW_VER")
+    #error "WXW_VER environment variable must be defined."
 #endif
 
-#define SETUPFILENAME  "wxMSW-" + GetENV("WXW_VER") + "-Setup"
+#define SETUPFILENAME  "wxMSW-" + GetEnv("WXW_VER") + "-Setup"
 
 
 
@@ -26,25 +32,25 @@ DefaultDirName={sd}\wxWidgets-{#WX_VERSION}
 DefaultGroupName=wxWidgets {#WX_VERSION}
 UsePreviousAppDir=no
 DisableProgramGroupPage=yes
-LicenseFile={#INNODIR}\docs\licence.txt
-InfoBeforeFile={#INNODIR}\docs\readme.txt
+LicenseFile={#WXW_DIR}\docs\licence.txt
+InfoBeforeFile={#WXW_DIR}\docs\readme.txt
 InfoAfterFile={#INFOFILE}
 OutputDir=c:\daily
 OutputBaseFilename={#SETUPFILENAME}
 PrivilegesRequired=none
-SetupIconFile={#INNODIR}\art\wxwin.ico
+SetupIconFile={#WXW_DIR}\art\wxwin.ico
 Compression=lzma
 SolidCompression=yes
 
 [Files]
 ; source files
-Source: "{#INNODIR}\*"; DestDir: "{app}"; Excludes: ".cvsignore,cocoa,dfb,mac,gtk,gtk1,motif,msdos,os2,wxWindows.xcod*,x11,debian,distrib,docs,misc,tests,wxPython,*.pch,*.pch++,*.pchmm"; Flags: ignoreversion recursesubdirs createallsubdirs
+Source: "{#WXW_DIR}\*"; DestDir: "{app}"; Excludes: ".cvsignore,cocoa,dfb,mac,gtk,gtk1,motif,msdos,os2,wxWindows.xcod*,x11,debian,distrib,docs,misc,tests,wxPython,*.pch,*.pch++,*.pchmm"; Flags: ignoreversion recursesubdirs createallsubdirs
 ; docs and helpfile
-Source: "{#INNODIR}\docs\htmlhelp\*"; DestDir: "{app}\docs\htmlhelp\";  Flags: ignoreversion recursesubdirs createallsubdirs
-Source: "{#INNODIR}\docs\licence.txt"; DestDir: "{app}\docs\";  Flags: ignoreversion recursesubdirs createallsubdirs
-Source: "{#INNODIR}\docs\readme.txt"; DestDir: "{app}\docs\";  Flags: ignoreversion recursesubdirs createallsubdirs
-Source: "{#INNODIR}\docs\changes.txt"; DestDir: "{app}\docs\";  Flags: ignoreversion recursesubdirs createallsubdirs
-Source: "{#INNODIR}\docs\msw\install.txt"; DestDir: "{app}\docs\msw";  Flags: ignoreversion recursesubdirs createallsubdirs
+Source: "{#WXW_DIR}\docs\htmlhelp\*"; DestDir: "{app}\docs\htmlhelp\";  Flags: ignoreversion recursesubdirs createallsubdirs
+Source: "{#WXW_DIR}\docs\licence.txt"; DestDir: "{app}\docs\";  Flags: ignoreversion recursesubdirs createallsubdirs
+Source: "{#WXW_DIR}\docs\readme.txt"; DestDir: "{app}\docs\";  Flags: ignoreversion recursesubdirs createallsubdirs
+Source: "{#WXW_DIR}\docs\changes.txt"; DestDir: "{app}\docs\";  Flags: ignoreversion recursesubdirs createallsubdirs
+Source: "{#WXW_DIR}\docs\msw\install.txt"; DestDir: "{app}\docs\msw";  Flags: ignoreversion recursesubdirs createallsubdirs
 ; NOTE: Don't use "Flags: ignoreversion" on any shared system files
 
 [INI]
@@ -61,4 +67,3 @@ Name: "{group}\Uninstall wxWidgets {#WX_VERSION}"; Filename: "{uninstallexe}"
 
 [UninstallDelete]
 Type: files; Name: "{app}\wx.url"
-