Problem solved. I tried svnadmin recover but it returned the End of File error. Next I looked into Andreas’ solution. The current file had “NULNULNULNUL” so I changed it to the last revision from the revs folder, and added the necessary filler text, so it read “2098 zzzzz zzzzz” (I found out you also have to include a carriage return).
Then svnadmin verify returned an “E200002: Serialized hash missing terminator” error after verifying revision 2097. I changed the current file to 2097 instead of 2098 (2098 was only 8kb), and everything is back up and running again. Thanks for your help, guys.