diff --git a/xpinstall/wizard/unix/src2/nsInstallDlg.cpp b/xpinstall/wizard/unix/src2/nsInstallDlg.cpp
index ca9eab9d5ede..ae70e0575e6c 100644
--- a/xpinstall/wizard/unix/src2/nsInstallDlg.cpp
+++ b/xpinstall/wizard/unix/src2/nsInstallDlg.cpp
@@ -335,7 +335,7 @@ nsInstallDlg::XPIProgressCB(const char *aMsg, int aVal, int aMax)
 
     static int updates = 0;
     char msg[64];
-    char *colon = NULL, *lastSlash = NULL;
+    const char *colon = NULL, *lastSlash = NULL;
 
     if (aMax > 0)
     {