Tweak incompatible-DB error text

chrome/locale/en-US/zotero/zotero.properties

@@ -136,7 +136,7 @@ dataDir.selectedDirEmpty.text			= The directory you selected is empty. To move a
 dataDir.selectedDirEmpty.useNewDir             = Use the new directory?
 dataDir.moveFilesToNewLocation                 = Be sure to move files from your existing Zotero data directory to the new location before reopening %1$S.
 dataDir.incompatibleDbVersion.title		= Incompatible Database Version
-dataDir.incompatibleDbVersion.text		= The selected database is too old to be used with this version of Zotero. Please first upgrade the database using Zotero 4.0 for Firefox or select a different data directory.
+dataDir.incompatibleDbVersion.text		= The selected data directory is too old to be used with this version of Zotero. Please first upgrade the data directory using Zotero 4.0 for Firefox or select a different directory.
 dataDir.migration.inProgress                               = Data directory migration in progress…
 dataDir.migration.failure.title                            = Data Directory Migration Error
 dataDir.migration.failure.partial.automatic.text = %1$S attempted to move your data directory to a new default location, but some files could not be transferred. Close any open attachment files and try again. You can also quit %2$S and attempt to move the remaining files manually.