Hi ,
you should check the radius/line of the hydraulic hose (left and right).The first pic shows the correct radius/line and position of the hose.
If the radius/line is too small it will crack the hose.
If the radius /line is too large, the hose will touch the wall of the trunk and rubbing the hose (red arrow-second pic).
For hose replacement , BMW has too disassemble the roof!
Pictures were taken from BMW Z4 E89 "zroadster Forum" in Germany.
regards ZettVier