Global option set (Managed, System Attribute) text values are missing, hence unable to open form (error while loading) with the mentioned attribute.
Attribute Name : Activity Type
Schema Name : activitypointer_activitytypecode
Missing texts for (values) 4406; 4402; 4401; 4206; 4214; 4208; 4209; 4209

Actual Option Set Key Value Pairs https://msdn.microsoft.com/en-us/library/gg328546.aspx#blmk_activityType
|
Value
|
Label
|
|
4201
|
Appointment
|
|
4202
|
Email
|
|
4204
|
Fax
|
|
4206
|
Case Resolution
|
|
4207
|
Letter
|
|
4208
|
Opportunity Close
|
|
4209
|
Order Close
|
|
4210
|
Phone Call
|
|
4211
|
Quote Close
|
|
4212
|
Task
|
|
4214
|
Service Activity
|
|
4251
|
Recurring Appointment
|
|
4401
|
Campaign Response
|
|
4402
|
Campaign Activity
|
|
4406
|
Bulk Operation
|
Thank you.