Editing other ODK forms with Kobo Forms


I am a new user of Kobo Forms. I had a form created with ODK Build which I converted into XML and opened in Kobo Forms. When I try to delete some of the questions, it shows an error message shown below


stack: TypeError: Cannot read property ‘b’ of null

at _Rc (:1899:545)

at ZIc (:1296:44)

at R8c (:436:17)

at Object.T8c [as Mf] (:1939:88381)

at cz (:425:46)

at Object.dz (:1121:16056)

at Og (:906:88)

at kr (:616:58)

at M4 (:557:48)

at Object.O4 (:1121:48788)

at cz (:425:46)

at Object.dz (:1121:16056)

at Og (:906:88)

at kr (:616:58)

at Z4 (:926:142)

at Object.e5 (:1121:49002)

at Object.l6 (:1121:51108)

at zr (:1081:573)

at Object.As (:1121:12478)

at hbc (http://www.kobotoolbox.org/koboform/KoBoFormDesigner/CB83027EA5801F610829F3416BE26762.cache.html:1886:79)

at HTMLDivElement. (http://www.kobotoolbox.org/koboform/KoBoFormDesigner/CB83027EA5801F610829F3416BE26762.cache.html:3100:228)

at $hb (http://www.kobotoolbox.org/koboform/KoBoFormDesigner/CB83027EA5801F610829F3416BE26762.cache.html:1149:30)

at bib (http://www.kobotoolbox.org/koboform/KoBoFormDesigner/CB83027EA5801F610829F3416BE26762.cache.html:2535:60)

at HTMLDivElement. (http://www.kobotoolbox.org/koboform/KoBoFormDesigner/CB83027EA5801F610829F3416BE26762.cache.html:1845:46): Cannot read property ‘b’ of null"

Can you please advice on what I can do as I need to edit the forms before uploading them. Thanks.