clarify error message
clarify error message

Original commit message from CVS:
clarify error message

mrchapp/gstreamer,StreamUtils/gstreamer,Lachann/gstreamer,jpakkane/gstreamer,justinjoy/gstreamer,centricular/gstreamer,Distrotech/gstreamer,Distrotech/gstreamer,Lachann/gstreamer,ylatuya/gstreamer,Distrotech/gstreamer,shelsonjava/gstreamer,ahmedammar/platform_external_gst_gstreamer,shelsonjava/gstreamer,StreamUtils/gstreamer,drothlis/gstreamer,cfoch/gstreamer,centricular/gstreamer,magcius/gstreamer,surround-io/gstreamer,krichter722/gstreamer,StreamUtils/gstreamer,cfoch/gstreamer,Lachann/gstreamer,ahmedammar/platform_external_gst_gstreamer,jpakkane/gstreamer,drothlis/gstreamer,krieger-od/gstreamer,krieger-od/gstreamer,lovebug356/gstreamer,lovebug356/gstreamer,ensonic/gstreamer,krieger-od/gstreamer,krieger-od/gstreamer,ensonic/gstreamer,centricular/gstreamer,mparis/gstreamer,drothlis/gstreamer,cfoch/gstreamer,surround-io/gstreamer,mparis/gstreamer,ensonic/gstreamer,krichter722/gstreamer,cfoch/gstreamer,cablelabs/gstreamer,justinjoy/gstreamer,mparis/gstreamer,collects/gstreamer,cfoch/gstreamer,krieger-od/gstreamer,lubosz/gstreamer,centricular/gstreamer,jpxiong/gstreamer,ylatuya/gstreamer,ensonic/gstreamer,cablelabs/gstreamer,ylatuya/gstreamer,cablelabs/gstreamer,Lachann/gstreamer,ahmedammar/platform_external_gst_gstreamer,cablelabs/gstreamer,jpxiong/gstreamer,Distrotech/gstreamer,Distrotech/gstreamer,shelsonjava/gstreamer,magcius/gstreamer,mrchapp/gstreamer,Lachann/gstreamer,mrchapp/gstreamer,jpakkane/gstreamer,collects/gstreamer,justinjoy/gstreamer,lovebug356/gstreamer,magcius/gstreamer,surround-io/gstreamer,ahmedammar/platform_external_gst_gstreamer,drothlis/gstreamer,StreamUtils/gstreamer,krichter722/gstreamer,drothlis/gstreamer,StreamUtils/gstreamer,lubosz/gstreamer,jpxiong/gstreamer,mparis/gstreamer,lubosz/gstreamer,justinjoy/gstreamer,centricular/gstreamer,magcius/gstreamer,ylatuya/gstreamer,lovebug356/gstreamer,cablelabs/gstreamer,lubosz/gstreamer,jpakkane/gstreamer,lubosz/gstreamer,collects/gstreamer,collects/gstreamer,collects/gstreamer,surround-io/gstreamer,mparis/gstreamer,ahmedammar/platform_external_gst_gstreamer,ensonic/gstreamer,shelsonjava/gstreamer,lovebug356/gstreamer,mrchapp/gstreamer,jpxiong/gstreamer,jpxiong/gstreamer,mrchapp/gstreamer,krichter722/gstreamer,ylatuya/gstreamer,magcius/gstreamer,jpakkane/gstreamer,surround-io/gstreamer,shelsonjava/gstreamer,justinjoy/gstreamer,krichter722/gstreamer