?Rebecca,
Here's some standard things to check and additional when there are rasters. I am sure you are familiar with some of these but to be complete, I will mention them. .
First off, check the log file in Spectrum (not Analyst). This is called the wrapper.log file located under your Spectrum server installation folder. It is in server\app\repository\logs. There may be an error in there that will be informative.
The next step would be to see if the raster displays in Spectrum spatial without using Analyst. You can use the Spectrum Spatial Manager or even the SOAP samples although those are a bit "geekier" to use. However it will do precisely what you tell it.
When you click on the named map containing the raster, the map will be displayed based on the center and zoom that you had in MapInfo Pro when the map was uploaded. So it should be based where you saw it in MapInfo Pro. It will also use the same projection that was used in MapInfo Pro so if raster reprojection was being used in Pro you might not get an image.
Knowing whether that works is important. It will be displayed on a white background.
If you click on the image to render the larger display, the projection may be changed. Lat/Long projections are not used but forced into Popular Mercator. Sometimes that will error since the raster cannot be reprojected. in Spectrum.
Knowing the details of what type of raster, what its native coordinate system is and whether there was reprojection in MapInfo Pro will be important. But if it displays in Spectrum Spatial, then something regarding projection or location must be the issue.
There may be an issue with transparency which can be enforced at the .tab file level (the RasterStyles ...) or in a layer override. That will be good to know.
Then there is the unlikely case of where the raster is being viewed in a place where there is no visible imagery. I can't say what would cause that but clearly if the image was being displayed in a place where you were not viewing in Analyst, you would see nothing. You still might see the error about no data when clicking.
If this does not help I would definitely put this into support and we will look at it.
Feel free to follow up here with more info or what you find.
Eric