Thank you for uploading the images. I have no problem at all to measure them with the current version of the SubframeSelector tool.

If you force measurements of circular PSFs, then eccentricity has to be zero. Eccentricity is defined as:

sqrt( 1 - (sy/sx)^{2} )

where sy and sx are the standard deviations of the fitted PSF function on the vertical and horizontal axes, respectively, and sx >= sy conventionally. In the circular case we have sx = sy, so eccentricity is equal to sqrt( 0 ) = 0. So this is the expected behavior.