Error saving raster

I have spent to much time in trying to solve a <raster>.save(filename) problem, and getting quite desperate. Any help is highly apreciated!

The code is like this
....
...
outM = Ln(meanAggregate)
outM.save("c:/temp/rastertest.gdb/xx")
....

I get the error:
ERROR 010240: Could not save raster dataset to c:\temp\rastertest.gdb\xx with output format FGDBR.

The strange thing is that if I do debugging in PyCharm and have a breakpoint on the saveline, it saves without any problem when I step trough the code.
If I remove the Ln function and just do a

....
outM = meanAggregate
outM.save("c:/temp/rastertest.gdb/xx")
....

it saves fine also (also when not debugging).


I have a lot of other rasters in the same python script that saves fine without any problem.

This is really a showstopper and I am getting quite desperate.


Thanks,
-helge