I've been trying to programmatically copy custom content type and its custom columns from one web to another for some time now, and I always get different errors or exceptions every time. After yet more tries, I received more strange and cryptic exception from Sharepoint after clicking onto a newly copied custom column in a custom content type. I checked the logs, and this is what I got:

Unknown SPRequest erorr occurred. More information: 0x80070002
Unable to locate the xml-definition for FieldName with FieldId 'guid without braces', exception: Microsoft.SharePoint.SPException: Catastrophic failure (Exception from HRESULT: 0x8000FFF (E_UNEXPECTED)) ---> System.Runtime.InteropServices.COMException...
... at Microsoft.SharePoint.Library.SPRequestInternalClass.GetGlobalContentTypeXml(String bstrUrl, Int32 type, UInt 32 lcid, Object varIdBytes...
Failed to find the content type schema for ct-1033-0x1000blahblahblahcontenttypeId while caching feature data.
Unknown SPRequest error occurred.  More informationL 0x8000ffff
Unable to locate the xml-definition for CType with SPContentTypeId '0x0100MorecontenttypeId', exception: Microsoft.SharePoint.SPException: Catastrophic failure(Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED)) ---> System.Runtime.InteropServices.COMException (0x8000FFFF): Catastrophic failure...
... at Microsoft.SharePoint.Library.SPRequestInternalClass.GetGlobalContentTypeXml(String bstrUrl, Int32 type, UInt 32 lcid, Object varIdBytes...

It failed to find quite a few content type schema. I'm confused with what Sharepoint is trying to do here, and why a simple process of copying a custom content type from one web to another just wouldn't work in contrast to the information found on the web e.g. this.

Appreciate any help to get over this problem. Thanks.