I have a problem with Livecycle Designer where whenever I try to preview any of my forms I get the message "There is a problem with Adobe Actobat/Reader. If it is running, please exit and try again. (507:507)", and instead of the prview I get an internet explorer style "This program cannot display the webpage" page.
It also seems to often make the Adobe Reader open up.
I am running 64 bit Windows 7 and have Adobe Reader X and Livecycle Designer 188.8.131.52.20091029.1.612548.
I have encountered the same issue . When I have Acrobat Pro and Adobe LC
designer installed in my machine.
After a re installing of Adobe Reader , this issue got resolved for me.
Please try that once.