0013039: [sr_feuser_register][pi1][main] by-ref conf-parameter will be NULL and content returns empty

In PHP 5.3 there's a backward incompatible change regarding by-ref params called by-value:

"Backward Incompatible Changes
...
The behaviour of functions with by-reference parameters called by value has changed. Where previously the function would accept the by-value argument, a warning is now emitted and all by-ref parameters are set to NULL."

sr_feuser_register::tx_srfeuserregister_pi1::main will not return the content because the second param &$conf will be set to null. In the FE you will get no content for any view at all.