Issue with cfimage captcha - coldfusion 11 linux (RHEL)

Hi all,

I have hit an issue with cfimage when attempting to generate a captcha.  Code works fine on the location (windows) dev version, so I assume this is likely to be linux permissions related or perhap a java issue. 

Quick heads up:

1) CF11 installed on Red Hat 7

2) Having checked the cfroot/cfusion/tmpCache/CFFileServlet/_cf_captcha and the png file that cfimage produces for a captcha request is there ready.

3) On the cf page the capture image does not show just a white area.  Looking at the source code the image scr is linking back to 'CFFileServlet/_cf_captcha/_captcha_img8757551929545998425.png'.

4) I have been attempting to resolve this issue for sometime and followed many of the suggestions around adding an Apache alias for CFFileServlet  and modifying mod_jk.conf etc but without success.

After following the installation guide for CF11, we did also update the version of Java as suggested.  Not sure if this is related but when using CF11 administrator, for example when adding a new mapping, if I click 'browse server' the directory structure does not display, just a blank dialog box.

Thanks,

Peter