[Tilecache] Tilecache with OL + Sublayers (sublayers) = Bad transparency mask

[Ivan Mincik]

On Mon, Apr 12, 2010 at 2:16 PM, Paul james <pauljame at gmail.com> wrote:
> Hello all!
>
> I have a Mapserver WMS + Openlayers application, using Geoext sublayers:
> - LAYER1
>    - SUBLAYER11
>    - SUBLAYER12
> -LAYER2
>    SUBLAYER21
> ...
>
>
> But when I try to turn on two or more layer´s sublayers, i got the error:
>
> An error occurred: Could not combine images: Is it possible that some layers
> are not 8-bit transparent images?
>
> (Error was: bad transparency mask) File "C:\inetpub\wwwroot\Openlayer\
> TileCache\Service.py", line 323, in cgiHandler format, image =
> service.dispatchRequest( params, path_info, req_method, host ) File
> "C:\inetpub\wwwroot\Openlayer\TileCache\Service.py", line 234, in
> dispatchRequest raise Exception("Could not combine images: Is it possible
> that some layers are not \n8-bit transparent images? \n(Error was: %s)" % E)
>
> Cache miss: -180.0,-90.0,0.0,90.0, Tile: x: 0, y: 0, z: 0, time:
> 0.828000068665 Cache miss: -180.0,-90.0,0.0,90.0, Tile: x: 0, y: 0, z: 0,
> time: 0.135999917984

Can You paste Your OUTPUTFORMAT  configuration for these layers ?