strange, since according to
they should be able to be read
Multiresolution Seamless Image Database (MrSID)
A proprietary compression technique especially for maintaining the quality of large images. Allows for a high compression ratio and fast access to large amounts of data at any scale. The MrSID Encoder is developed and supported by LizardTech, Inc.
Supports generations 2, 3, and 4.
sSingle file—extension *.sid
World file—extension *.sdw
8-, and 16-bit unsigned integer
Generation 2 and generation 3—limited to 1 or 3 bands
anything special? are you adding them to an empty map?