@@ -122,11 +122,13 @@
 
 			set ver [lindex $pkginfo 0]
 			set arch [lindex $pkginfo 1]
 			set server [lindex $pkginfo 2]
 
-			set pkgdir [file join $rootdir $extension$ver]
+			set safe_ext_name [string map [list ":" "_"] $extension]
+
+			set pkgdir [file join $rootdir ${safe_ext_name}$ver]
 			file mkdir $pkgdir $::teapotclient::pkgcachedir
 
 			set url "http://$server/package/name/$extension/ver/$ver/arch/$arch/file"
 			set urlcachefile [file join $::teapotclient::pkgcachedir [::md5::md5 -hex $url]]
 
@@ -163,11 +165,11 @@
 					}
 				}
 				"(^| )text($| )" {
 					unset -nocomplain fd
 
-					set extfile [file join $pkgdir ${extension}.tcl]
+					set extfile [file join $pkgdir ${safe_ext_name}.tcl]
 					set idxfile [file join $pkgdir pkgIndex.tcl]
 
 					catch {
 						file copy -force -- $urlcachefile $extfile